AS Unit 1 particles questionss by nuhman10

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									                                                AS Unit 1: Particles

1.   (a)   (i)    State two differences between a proton and a positron.

                  difference 1 ......................................................................................................

                  ...........................................................................................................................

                  difference 2 ......................................................................................................

                  ...........................................................................................................................



           (ii)   A narrow beam of protons and positrons travelling at the same speed enters a
                  uniform magnetic field. The path of the positrons through the field is shown in
                  figure 1.

                  Sketch on figure 1 the path you would expect the protons to take.

                                                                                                                          boundary of the
                                                                                                                          uniform magnetic
                                  positrons                                                                               field into the plane
                                                                                                                          of the diagram at
                                                                                                                          90°


                                                               ×                                      ×
           protons
           positrons                                                               ×

                                                               ×                                      ×

                                                                     figure 1




                                                                                                                                                 1
                                             AS Unit 1: Particles


      (iii)   Explain why protons take a different path to that of the positrons.

              ...........................................................................................................................

              ...........................................................................................................................

              ...........................................................................................................................

              ...........................................................................................................................

              ...........................................................................................................................

              ...........................................................................................................................
                                                                                                                                            (5)



(b)   Figure 2 shows five isotopes of carbon plotted on a grid in which the vertical axis
      represents the neutron number N and the horizontal axis represents the proton number Z.
      Two of the isotopes are stable, one is a beta minus emitter and two are positron emitters.


                       9
                                        14
                                         6C
                       8
                                        13
                                         6C
                       7
                                        12
                                         6C
                       6
                                        11
                                         6C
                       5
                                        10
                                         6C
               N       4
                               5             6            7            8             9
                                   Z

                                             figure 2



      (i)     Which isotope is a beta minus emitter?

              ...........................................................................................................................




                                                                                                                                             2
                                                   AS Unit 1: Particles


           (ii)      Which of the two positron emitters has the shorter half-life? Give a reason for your
                     choice.

                     ...........................................................................................................................

                     ...........................................................................................................................

                     ...........................................................................................................................
                                                                                                                                                        (3)



     (c)   A positron with kinetic energy 2.2 MeV and an electron at rest annihilate each other.
           Calculate the average energy of each of the two gamma photons produced as a result of
           this annihilation.

           .....................................................................................................................................

           .....................................................................................................................................

           .....................................................................................................................................

           .....................................................................................................................................
                                                                                                                                                        (2)
                                                                                                                                           (Total 10 marks)




2.   (a)   A positron is emitted from a nucleus when a proton changes to a neutron in the nucleus.
           The Feynman diagram for this process is shown in the figure below.

           Identify the particles labelled A, B, C and D in the diagram.

                                                                                C
                                                                                        D
                                                  A



                                                                      B



                                               up quark

           particle A ...............................................

           particle B ...............................................

           particle C ...............................................

           particle D ...............................................


                                                                                                                                                         3
                                                   AS Unit 1: Particles

     (b)   Name an exchange particle of the weak nuclear force.

           .....................................................................................................................................



     (c)   State one difference between the photon and the exchange particle of the weak nuclear
           force.

           .....................................................................................................................................
                                                                                                                                             (Total 7 marks)




3.   A carbon-14 nucleus undergoes – decay, forming a new nucleus, releasing a – particle and
     one other particle which is difficult to detect.

     (a)   Write down the proton number and the nucleon number of the new nucleus.

           proton number ............................................................................................................

           nucleon number ..........................................................................................................



     (b)   Name the particle which is difficult to detect.

           .....................................................................................................................................



     (c)   Name the baryons and leptons involved in the decay.

           baryons .......................................................................................................................

           leptons ........................................................................................................................



     (d)   Give the quark structure for the neutron and the proton.

           neutron ........................................................................................................................

           proton .........................................................................................................................

           Hence state the quark transformation that occurs during – decay.

           .....................................................................................................................................
                                                                                                                                             (Total 7 marks)




                                                                                                                                                          4
                                                   AS Unit 1: Particles
4.   The Feynman diagram represents the emission of a beta particle from a neutron-rich nucleus. A
     and B each represent a quark.

                                                                            D

                                                    B                                –

                                                                C


                                            A




     (a)   Identify the particles labelled A, B, C and D.

           A ................................................................................................................................

           B ................................................................................................................................

           C ................................................................................................................................

           D ................................................................................................................................



     (b)   The beta particle in the Feynman diagram was produced when particle C decayed.
           State two differences between particle C and  gamma photon.

           .....................................................................................................................................

           .....................................................................................................................................

           .....................................................................................................................................

           .....................................................................................................................................
                                                                                                                                             (Total 6 marks)




                                                                                                                                                          5
                                                  AS Unit 1: Particles


5.   (a)   State whether or not each of the following properties of a baryon is conserved when it
           decays by the weak interaction.

           charge .................................................................................................................

           baryon number ...................................................................................................

           strangeness .........................................................................................................
                                                                                                                                                        (2)



     (b)   State, with a reason, whether or not each of the following particle reactions is possible.

           (i)      p + –  K– + +

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................



           (ii)     p + v  n = e+

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................
                                                                                                                                                        (4)
                                                                                                                                            (Total 6 marks)




6.   (a)   There are a number of ways in which u, d and s quarks and their associated antiparticles
           may be combined to form mesons. Use the table ‘properties of quarks’, in the Data Sheet,
           to complete parts (i) to (iii).

           (i)      The kaon K– has a strangeness –1. Write down its quark composition.

                    K– .....................................................................................................................




                                                                                                                                                         6
                                                   AS Unit 1: Particles


           (ii)      The kaons K0 and K+ both have strangeness +1. Write down their quark
                     composition.

                     K0 .....................................................................................................................

                     K+ ......................................................................................................................



           (iii)     Write down the quark composition of a proton.

                     p ........................................................................................................................
                                                                                                                                                         (5)



     (b)   In the strong interaction,

                     K– + p  K0 + K+                                      +       X,

           deduce the quark composition of, and state the type of, hadron represented by X.

           .....................................................................................................................................

           .....................................................................................................................................
                                                                                                                                                         (2)



     (c)   A positive muon may decay to a positron and two neutrinos. Write down an equation
           representing the muon decay.

                     + 
                                                                                                                                                         (2)
                                                                                                                                             (Total 9 marks)




                                                                      14
7.   A neutral atom of carbon is represented by                        6   C.

     (i)   Name the constituents of this atom and state how many of each are present.

           .....................................................................................................................................

           .....................................................................................................................................

           .....................................................................................................................................




                                                                                                                                                          7
                                                     AS Unit 1: Particles


     (ii)    Which constituent of an atom has the largest charge-to-mass ratio?

             .....................................................................................................................................



     (iii)   Carbon has several isotopes. Explain the term isotope.

             .....................................................................................................................................

             .....................................................................................................................................
                                                                                                                                               (Total 6 marks)




8.   (a)     (i)       How many quarks are there in a baryon?

                       ...........................................................................................................................



             (ii)      Hadrons fall into two groups, baryons being one of them. What name is given to
                       the other group of hadrons?

                       ...........................................................................................................................



             (iii)     What distinguishes hadrons from other particles?

                       ...........................................................................................................................

                       ...........................................................................................................................
                                                                                                                                                           (3)



     (b)     (i)       Give the name of one antiparticle that is also a lepton.

                       ...........................................................................................................................



             (ii)      What distinguishes leptons from other particles?

                       ...........................................................................................................................

                       ...........................................................................................................................
                                                                                                                                                           (2)




                                                                                                                                                            8
                                      AS Unit 1: Particles


     (c)   A neutron decays by the weak interaction.
           Complete the equation.

                 n      p + ................ + ..............
                                                                                                     (2)



     (d)   The Feynman diagram representing electron capture is given below. Complete the
           labelling of the diagram.




                                                 W+


                                                                             e–




                                                                                                     (3)
                                                                                        (Total 10 marks)




           232
9.   (a)    90Th is a neutral atom of thorium. How many protons, neutrons and electrons does it
           contain?

                                      ........................   protons

                                      ........................   neutrons

                                      ........................   electrons
                                                                                                     (2)




                                                                                                      9
                                                 AS Unit 1: Particles


             Y
      (b)    XTh is a neutral atom of a different isotope of thorium which contains Z electrons. Give
            possible values for X, Y and Z.

                                                 X = ....................................................

                                                 Y = ....................................................

                                                 Z = .....................................................
                                                                                                                                                       (3)
                                                                                                                                           (Total 5 marks)




10.   In a particle accelerator a proton and an antiproton, travelling at the same speed, undergo a
      head-on collision and produce subatomic particles.

      (a)   The total kinetic energy of the two particles just before the collision is 3.2  10–10 J.

            (i)    What happens to the proton and antiproton during the collision?

                   ...........................................................................................................................

                   ...........................................................................................................................



            (ii)   State why the total energy after the collision is more than 3.2 × 10–10 J.

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................
                                                                                                                                                       (2)




                                                                                                                                                       10
                                                    AS Unit 1: Particles


      (b)   In a second experiment the total kinetic energy of the colliding proton and antiproton is
            greater than 3.2  10–10 J.

            State two possible differences this could make to the subatomic particles produced.

            1 .................................................................................................................................

            2 .................................................................................................................................
                                                                                                                                                          (2)
                                                                                                                                              (Total 4 marks)




11.   (a)   The negative kaon, K–, has a strangeness of –1.
            Write down its quark composition.

            ....................................................................................................................................
                                                                                                                                                          (2)




      (b)   The kaon, K– may decay into a muon and an antineutrino in the following way:

                                                            K–  –                 +      μ.

            (i)       Complete the following table using ticks and crosses as indicated in the first row.

                                                                                K–                  –                  μ
                                          charged particle
                                          hadron
                                          meson
                                          baryon
                                          lepton



            (ii)      In the decay shown above, charge is conserved. Give another quantity that is
                      conserved and a quantity that is not conserved in the decay of K–.

                      quantity conserved ..........................................................................................

                      quantity not conserved ....................................................................................
                                                                                                                                                          (6)




                                                                                                                                                          11
                                            AS Unit 1: Particles


(c)   The Feynman diagram below represents the + decay process.


                                                                                   D

                                                                                             +
                                              B


                                                                        C


                                                    A




      (i)     What quantity changes continuously in moving from the bottom to the top of the
              diagram?

              .........................................................................................................................



      (ii)    Name the particles represented by the letters A to D.

              A ......................................................................................................................

              B ......................................................................................................................

              C ......................................................................................................................

              D ......................................................................................................................



      (iii)   What type of interaction is responsible for + decay?

              .........................................................................................................................
                                                                                                                                                 (6)
                                                                                                                                    (Total 14 marks)




                                                                                                                                                 12
                                                    AS Unit 1: Particles


                                                                                                    59
12.   (a)   The most abundant isotope of cobalt is represented by                                   27 Co   .

            How many protons, neutrons and orbital electrons are there in a neutral atom of this
            element?

            ........................................ protons

            ........................................ neutrons

            ........................................ electrons
                                                                                                                                                          (2)



                                                                                                                        61
      (b)   How is the nuclide that has one less proton than the nickel nuclide,                                        28 Ni ,   represented?

            .....................................................................................................................................
                                                                                                                                                          (2)



      (c)   (i)       The heaviest isotope of hydrogen, whose nucleon number is 3, is called tritium.
                      How is tritium represented?

                      ...........................................................................................................................



            (ii)      Calculate the charge per unit mass, in C kg–1, for a tritium nucleus.

                      ...........................................................................................................................

                      ...........................................................................................................................

                      ...........................................................................................................................
                                                                                                                                                          (3)
                                                                                                                                              (Total 7 marks)




13.   (i)   Calculate the energy, in J, of a photon of wavelength 4.50 × 10–7 m.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................




                                                                                                                                                          13
                                                     AS Unit 1: Particles


      (ii)   Calculate the speed of an electron which has the same wavelength as the photon in part
             (i).

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................

             .....................................................................................................................................
                                                                                                                                               (Total 5 marks)




14.   (a)    An electron and a positron travelling with equal speeds meet head-on and annihilate,
             releasing 2.0 × 106 eV of energy. This energy is shared equally by two photons.

             Calculate the energy, in J, of each photon.

             .....................................................................................................................................

             .....................................................................................................................................
                                                                                                                                                           (1)



      (b)    Complete the tables by writing true or false in the right hand column.

             The first table has been completed as an example.

               a neutron is a fundamental particle                                                               false
               an antineutron is not a fundamental particle                                                       true

               a neutron is a stable particle
               an antineutron is an unstable particle


               a neutron has a rest mass of 1.67 × 10–27 kg
               a antineutron has a rest mass of –1.67 ×10–27 kg

               a neutron has no charge
               an antineutron has a charge of 1.60 × 10–19 C
                                                                                                                                                           (3)




                                                                                                                                                           14
                                                 AS Unit 1: Particles


      (c)   (i)    The exchange particle responsible for the weak interaction is either a W boson or a
                   Z boson.

                   Give the name of another exchange particle and the interaction for which it is
                   responsible.

                   exchange particle ....................................................................

                   interaction ...............................................................................



            (ii)   An antineutrino may be detected via its weak interaction with a proton as shown in
                   the Feynman diagram.

                   Complete the labelling on the diagram.




                                                                                          –
                                                                                          ve


                                                              p



                                                                                                                                                       (5)
                                                                                                                                           (Total 9 marks)




15.   (a)   (i)    How do hadrons differ from all other subatomic particles?

                   ...........................................................................................................................

                   ...........................................................................................................................



            (ii)   Give the quark composition of the following particles.

                   neutron .............................................................................................................

                   neutral pion ......................................................................................................

                   ...........................................................................................................................


                                                                                                                                                       15
                                              AS Unit 1: Particles

      (iii)     Classify the following as either leptons, baryons or mesons.

                kaon ................................................................................................................

                muon ................................................................................................................
                                                                                                                                              (5)



(b)   Which is the most stable baryon?

      .....................................................................................................................................
                                                                                                                                              (1)




(c)   This table may be useful in answering the questions which follow.

            particle           baryon number                   lepton number                    strangeness
               –                            0                              0                            0
                p                            1                              0                            0

                p                          –1                               0                            0

                e–                           0                              1                            0

               e+                            0                            –1                             0

               ve                            0                            –1                             0


      The particle X, which is a strange particle, decays in the following way:

                                                               X  – + p



      (i)       State whether X is a meson, a baryon or a lepton.

                ...........................................................................................................................




                                                                                                                                              16
                                                    AS Unit 1: Particles


            (ii)      Use conservation laws to decide whether each of the following decays of the – is
                      possible. Give a reason for your answer.

                      (A)                                           –  e+ + e

                                Is this decay possible? ...................................................

                                reason ....................................................................................................

                      (B)                                            π –  p  e–  e

                                Is this decay possible? ...................................................

                                reason ....................................................................................................
                                                                                                                                                         (5)
                                                                                                                                            (Total 11 marks)




                               37
16.   An atom of argon         18 Ar    is ionised by the removal of two orbiting electrons.

      (a)   How many protons and neutrons are there in this ion?

            ....................................... protons

            ...................................... neutrons
                                                                                                                                                         (2)



      (b)   What is the charge, in C, of this ion?

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                         (2)



      (c)   Which constituent particle of this ion has

            (i)       a zero charge per unit mass ratio,

                      ............................................................................................................................

                      ............................................................................................................................




                                                                                                                                                         17
                                                    AS Unit 1: Particles


            (ii)      the largest charge per unit mass ratio?

                      ............................................................................................................................
                                                                                                                                                          (2)



      (d)   Calculate the percentage of the total mass of this ion that is accounted for by the mass of
            its electrons.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                          (3)
                                                                                                                                              (Total 9 marks)




17.   (a)   (i)       What class of particle is represented by the combination of three antiquarks, q q q ?

                      ...........................................................................................................................



            (ii)      Name a hadron that has an antiparticle identical to itself.

                      ...........................................................................................................................
                                                                                                                                                          (3)




      (b)   The kaon K+ has a strangeness of +1.

            (i)       Give its quark composition.

                      ...........................................................................................................................

                      ...........................................................................................................................




                                                                                                                                                          18
                                      AS Unit 1: Particles


(ii)    The K+ may decay via the process

                                                     K+ + + 0.

        State the interaction responsible for this decay.

        ...........................................................................................................................



(iii)   The K+ may also decay via the process

                                                 K+  + + .

        Change each particle in this equation to its corresponding antiparticle in order to
        complete an allowed decay process for the negative kaon K–.

                                                 K– 



(iv)    Into what class of particle can both the + and the  be placed?

        ...........................................................................................................................



(v)     State one difference between a positive muon, +, and a positron, e+.

        ...........................................................................................................................
                                                                                                                                      (6)




                                                                                                                                      19
                                                   AS Unit 1: Particles


      (c)   The figure below shows a partially completed Feynman diagram of + decay.




                                                                                         W+



                                                                         p




            Complete the figure and label all the particles involved.
                                                                                                                                                        (3)
                                                                                                                                           (Total 12 marks)




                                                                                                                     14
18.   (a)   How many protons, neutrons and electrons are there in an atom of                                          6C?


            ....................................... protons

            ....................................... neutrons

            ....................................... electrons
                                                                                                                                                        (2)




      (b)   The 14 C atom loses two electrons.
                  6
            For the ion formed;

            (i)      calculate its charge in C,

                     ...........................................................................................................................



            (ii)     state the number of nucleons it contains,

                     ...........................................................................................................................




                                                                                                                                                        20
                                                  AS Unit 1: Particles


                                                  charge
            (iii)   calculate the ratio                  in C kg–1.
                                                   mass

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................
                                                                                                                                                        (4)
                                                                                                                                            (Total 6 marks)




19.   (a)   A neutrino may interact with a neutron in the following way

                                                               e + n  p + e–.



            (i)     Name the fundamental force responsible for this interaction.

                    ...........................................................................................................................



            (ii)    Complete the Feynman diagram for this interaction and label all the particles
                    involved.


                                                                             W–
                                                                                               ve
                                                                n


                                                                                                                                                        (3)




                                                                                                                                                        21
                                                   AS Unit 1: Particles


      (b)   The neutral kaon, which is a meson of strangeness +1, may decay in the following way

                                                                  K°  + + –.

            (i)      Apart from conservation of energy and momentum, state two other conservation
                     laws obeyed by this decay and one conservation law which is not obeyed.

                     ......................................................................... conservation law is obeyed

                     ......................................................................... conservation law is obeyed

                     ................................................................... conservation law is not obeyed



            (ii)     Deduce the quark composition of all the particles involved in the K° decay.

                     ...........................................................................................................................

                     ...........................................................................................................................

                     ...........................................................................................................................

                     ...........................................................................................................................

                     K° .........................................................

                     + ..........................................................

                     – ..........................................................
                                                                                                                                                         (6)
                                                                                                                                             (Total 9 marks)




20.   (a)   A stable atom contains 28 nucleons.

            Write down a possible number of protons, neutrons and electrons contained in the atom.

            ....................................... protons

            ...................................... neutrons

            ...................................... electrons
                                                                                                                                                         (2)




                                                                                                                                                         22
                                                  AS Unit 1: Particles


      (b)   An unstable isotope of uranium may split into a caesium nucleus, a rubidium nucleus and
            four neutrons in the following process.

                                    236                      137                      X                        1
                                         U        
                                                              Cs                  Rb                       40 n
                                      92                       55                    37

            (i)     Explain what is meant by isotopes.

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................



                                                                              137
            (ii)    How many neutrons are there in the                         55 Cs    nucleus?

                    ...........................................................................................................................



                                                  charge
            (iii)   Calculate the ratio                  , in C kg–1, for the                236
                                                                                              92   U nucleus.
                                                   mass

                    ...........................................................................................................................

                    ...........................................................................................................................

                    ...........................................................................................................................



            (iv)    Determine the value of X for the rubidium nucleus.

                    ...........................................................................................................................

                                                                                                    X = ....................................
                                                                                                                                                        (6)
                                                                                                                                            (Total 8 marks)




21.   (a)   (i)     Underline the particles in the following list that may be affected by the weak
                    interaction.

                    positron                    neutron                     photon                 neutrino            positive pion




                                                                                                                                                        23
                                          AS Unit 1: Particles


      (ii)   Underline the particles in the following list that may be affected by the
             electromagnetic force.

             electron                   antineutrino               proton          neutral pion             negative muon
                                                                                                                                           (4)



(b)   A positive muon may decay in the following way,

                                                 µ+  e+ + ν e + ν µ
      (i)    Exchange each particle for its corresponding antiparticle and complete the equation
             to show how a negative muon may decay.

                      µ–     



      (ii)   Give one difference and one similarity between a negative muon and an electron.

             difference ......................................................................................................

             similarity .......................................................................................................
                                                                                                                                           (3)



(c)   Complete the Feynman diagram, which represents electron capture, by labelling all the
      particles involved.




                                                 ---                           ---
                                                              –
                                                         W

                                                  e–                              ---

                                                                                                                                           (3)
                                                                                                                              (Total 10 marks)




                                                                                                                                           24
                                                    AS Unit 1: Particles


                                                                                                                               22
22.   (a)   Give the number of nucleons and the number of electrons in an atom of                                              11   Na.

            nucleons ..............................................

            electrons ..............................................
                                                                                                                                                            (2)



                        22
      (b)   The isotope 11 Na is a positron emitter. In positron emission an up quark undergoes the
            following change,

                                                              u  d + + + ve.

            Show that charge, lepton number and baryon number are conserved in this decay.

            charge .........................................................................................................................

            lepton number ...........................................................................................................

            baryon number ...........................................................................................................
                                                                                                                                                            (3)



      (c)   Describe what happens when a positron collides with an electron.

            .................................................................................................................................

            .................................................................................................................................

            .................................................................................................................................
                                                                                                                                                            (2)
                                                                                                                                                (Total 7 marks)




23.   (a)   Quarks may be combined together in a number of ways to form sub-groups of hadrons.
            Name two of these sub-groups and for each, state its quark composition.

            sub-group 1 .............................................................................................................

            .................................................................................................................................

            sub-group 2 .............................................................................................................

            .................................................................................................................................
                                                                                                                                                            (3)




                                                                                                                                                            25
                                                 AS Unit 1: Particles


      (b)   A free neutron is an unstable particle.

            (i)    Complete the following to give an equation that represents the decay of a neutron.

                                                    n



            (ii)   Describe the change that occurs to the quark structure when a neutron decays.

                   .......................................................................................................................

                   .......................................................................................................................

                   .......................................................................................................................

                   .......................................................................................................................

                   .......................................................................................................................
                                                                                                                                                         (4)
                                                                                                                                             (Total 7 marks)




                                                                        239
24.   (a)   (i)    Determine the charge, in C, of a                      92 U    nucleus.

                   ...........................................................................................................................

                   ...........................................................................................................................



            (ii)   A positive ion with a 239 U nucleus has a charge of 4.80 × 10–19 C.
                                          92
                   Determine how many electrons are in this ion.

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................
                                                                                                                                                         (4)




                                                                                                                                                         26
                                                     AS Unit 1: Particles


     (b)      A   239
                   92 U   nucleus may decay by emitting two – particles to form a plutonium nucleus
              X
              Y   Pu . State what X and Y represent and give the numerical value of each.

              X ....................….......................................................................................………….

              ........................….......................................................................................………….

              Y ....................….......................................................................................………….

              ........................….......................................................................................………….
                                                                                                                                                           (4)
                                                                                                                                               (Total 8 marks)




Cs nucleus?

                       ...........................................................................................................................




                                                                                                                                                           27
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                       28
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                       29
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                       30
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                       31
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             AS Unit 1: Particles
charge 236
        92
 mass




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                                           AS Unit 1: Particles
(a)   (i)    State the rest mass, in kg, of the ß+ particle.

             ...........................................................................................................................



      (ii)   Calculate the energy of the  photon.

             ...........................................................................................................................

             ...........................................................................................................................

             ...........................................................................................................................

             ...........................................................................................................................




                                                                                                                                           57
                                                    AS Unit 1: Particles


            (iii)     Determine the energy of the  photon in MeV.

                      ...........................................................................................................................

                      ...........................................................................................................................
                                                                                                                                                         (6)




      (b)   Name the fundamental interaction or force responsible for + decay.

            ................................................................................................................................…
                                                                                                                                                         (1)




      (c)   + decay may be represented by the Feynman diagram.



                                                                                      C
                                                                                                    +
                                                               A
                                                                            B


                                                               p



            Name the particles represented by A, B and C.

            A ......................…..

            B .....................…...

            C …........................
                                                                                                                                                         (3)
                                                                                                                                            (Total 10 marks)




26.   Some subatomic particles are classified as hadrons.

      (a)   What distinguishes a hadron from other subatomic particles?

            ................................................................................................................................…

            ................................................................................................................................…
                                                                                                                                                         (1)




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                                                    AS Unit 1: Particles
      (b)   Hadrons fall into two subgroups. Name each subgroup and describe the general
            structure of each.

            subgroup 1 .................................................................................................................

            ................................................................................................................................…

            subgroup 2 ..............................................................………......................................

            ................................................................................................................................…
                                                                                                                                                          (3)



      (c)   The following equation represents an event in which a positive muon collides with a
            neutron to produce a proton and an antineutrino.

                                                             n + +  p + v μ .

            Show that this equation obeys the conservation laws of charge, lepton number and baryon
            number.

            ................................................................................................................................…

            ................................................................................................................................…

            ................................................................................................................................…
                                                                                                                                                          (3)
                                                                                                                                              (Total 7 marks)




27.   (a)   Name the constituent of an atom which

            (i)       has zero charge,

                      ............................................................................................................................

            (ii)      has the largest charge to mass ratio,

                      ............................................................................................................................

            (iii)     when removed leaves a different isotope of the element.

                      ............................................................................................................................
                                                                                                                                                          (3)




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                                           AS Unit 1: Particles


(b)   An  particle is the same as a nucleus of helium,                           4
                                                                                  2   He.
      The equation

                                             229                           X
                                                    Th                         Ra + 
                                              90                           Y

      represents the decay of thorium by the emission of an  particle.

      Determine

      (i)    the values of X and Y, shown in the equation,

             X = .....................

             Y = .....................



                            mass of X Ra nucleus
                                    Y
      (ii)   the ratio
                              mass of  particle

             .............................................................................................................................

             .............................................................................................................................

             .............................................................................................................................
                                                                                                                                                 (3)
                                                                                                                                     (Total 6 marks)




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                                                  AS Unit 1: Particles


28.   (a)   (i)     Name a force which acts between an up quark, u, and an electron. Explain, with
                    reference to an exchange particle, how this force operates.

                    You may be awarded marks for the quality of written communication in your
                    answer.

                    .............................................................................................................................

                    .............................................................................................................................

                    .............................................................................................................................

                    .............................................................................................................................

                    .............................................................................................................................

                    .............................................................................................................................

                    .............................................................................................................................

                    .............................................................................................................................



            (ii)    With what particle must a proton collide to be annihilated?

                    .............................................................................................................................
                                                                                                                                                       (4)




      (b)   A sigma plus particle, +, is a baryon.

            (i)     How many quarks does the + contain?

                    .............................................................................................................................

            (ii)    If one of these quarks is an s quark, by what interaction will it decay?

                    .............................................................................................................................

            (iii)   Which baryon will the + eventually decay into?

                    .............................................................................................................................
                                                                                                                                                       (3)
                                                                                                                                            (Total 7marks)




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                                                    AS Unit 1: Particles


29.   The equation

                                                             p                n +  + + e

      represents the emission of a positron from a proton.



      (a)   Energy and momentum are conserved in this emission.
            What other quantities are conserved in this emission?

            .......................................................................................................................................

            .......................................................................................................................................

            .......................................................................................................................................

            .......................................................................................................................................
                                                                                                                                                      (3)



      (b)   Draw the Feynman diagram that corresponds to the positron emission represented in
            the equation.




                                                                                                                                                      (4)




                                                                                                                                                      62
                                                    AS Unit 1: Particles



      (c)   Complete the following table using ticks                              and crosses             .

                   particle                    fundamental                            meson                      baryon                  lepton
                                                 particle
                        p
                        n
                       +
                        e
                                                                                                                                                         (4)
                                                                                                                                            (Total 11 marks)




30.   (a)   What are isotopes?

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                         (2)




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                                                 AS Unit 1: Particles


                                                                                                15
      (b)   One of the isotopes of nitrogen may be represented by                                7   N.

            (i)    State the number of each type of particle in its nucleus.

                   ...........................................................................................................................

                   ...........................................................................................................................

                                                    charge
            (ii)   Determine the ratio                     , in C kg–1, of its nucleus.
                                                     mass

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................

                   ...........................................................................................................................
                                                                                                                                                       (4)



                                                                                  15
      (c)   (i)    What is the charge, in C, of an atom of                         7   N from which a single electron has been
                   removed?

                   ...........................................................................................................................

            (ii)   What name is used to describe an atom from which an electron has been removed?

                   ...........................................................................................................................
                                                                                                                                                       (2)
                                                                                                                                           (Total 8 marks)




31.   The equation represents the collision of a neutral kaon with a proton, resulting in the production
      of a neutron and a positive pion.

                                                           K° + p                 n + π+




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                                                    AS Unit 1: Particles


      (a)   Show that this collision obeys three conservation laws in addition to energy and
            momentum.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                          (3)



      (b)   The neutral kaon has a strangeness of +1.
            Write down the quark structure of the following particles.

            K° ..............................................

            + ...............................................

            p .................................................
                                                                                                                                                          (4)
                                                                                                                                              (Total 7 marks)




32.   (a)   (i)       Complete the equation that represents the collision between a proton and an
                      antineutrino.

                                                                            
                                                                     ve  p 



            (ii)      What fundamental force is responsible for the interaction shown in part (i)?

                      ...........................................................................................................................



            (iii)     Name an exchange particle that could be involved in this interaction.

                      ...........................................................................................................................
                                                                                                                                                          (4)




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                                                    AS Unit 1: Particles


      (b)   Describe what happens in pair production and give one example of this process.

            You may be awarded marks for the quality of written communication in your answer.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                          (3)
                                                                                                                                              (Total 7 marks)




                                                                                 14
33.   A radioactive isotope of carbon is represented by                          6 C.


      (a)   Using the same notation, give the isotope of carbon that has two fewer neutrons.

            .....................................................................................................................................
                                                                                                                                                          (1)



      (b)   Calculate the charge on the ion formed when two electrons are removed from an atom
            of 14 C.
               6


            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                          (2)




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                                                    AS Unit 1: Particles


                                                charge                                                       14
      (c)   Calculate the value of                     for the nucleus of an atom of                         6 C.
                                                 mass

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                          (2)
                                                                                                                                              (Total 5 marks)




34.   (a)   (i)       Give an example of an exchange particle other than a W+ or W– particle, and state
                      the fundamental force involved when it is produced.

                      exchange particle ......................................................................................................

                      fundamental force .....................................................................................................



            (ii)      State what roles exchange particles can play in an interaction.

                      ...........................................................................................................................

                      ...........................................................................................................................

                      ...........................................................................................................................
                                                                                                                                                          (4)




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                                                     AS Unit 1: Particles


      (b)   From the following list of particles,

            p         n          νe       e+          –       0

            identify all the examples of

            (i)       hadrons, .............................................................................................................

            (ii)      leptons, ...............................................................................................................

            (iii)     antiparticles, .......................................................................................................

            (iv)      charged particles. ................................................................................................
                                                                                                                                                          (4)
                                                                                                                                              (Total 8 marks)




35.   (a)   An ion of plutonium                239
                                                94   Pu has an overall charge of +1.6 × 10–19C.

            For this ion state the number of

            (i)       protons ..........................................

            (ii)      neutrons .......................................

            (iii)     electrons .......................................
                                                                                                                                                          (3)



      (b)   Plutonium has several isotopes.

            Explain the meaning of the word isotopes.

            .....................................................................................................................................

            .....................................................................................................................................

            .....................................................................................................................................
                                                                                                                                                          (2)
                                                                                                                                              (Total 5 marks)




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                                                    AS Unit 1: Particles


36.   Under certain conditions a γ photon may be converted into an electron and a positron.

      (a)   What is this process called?

            .....................................................................................................................................
                                                                                                                                                          (1)

      (b)   (i)       Explain why there is a minimum energy of the γ photon for this conversion to take
                      place and what happens when a γ photon has slightly more energy than this value.

                      ...........................................................................................................................

                      ...........................................................................................................................

                      ...........................................................................................................................

                      ...........................................................................................................................

                      ...........................................................................................................................



            (ii)      Using values from the data sheet calculate this minimum energy in MeV.

                      ...........................................................................................................................

                      ...........................................................................................................................
                                                                                                                                                          (3)



      (c)   Under suitable conditions, a γ photon may be converted into two other particles rather
            than an electron and positron.
            Give an example of the two other particles it could create.

            .....................................................................................................................................
                                                                                                                                                          (1)
                                                                                                                                              (Total 5 marks)



37.   (a)   Complete the following equations

                                p         +          e–                    ____         +      ____


                                n         +                                 p         +      ____


                                p         +          p                        p         +         p         +         K–      +         ____
                                                                                                                                                          (4)




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                                              AS Unit 1: Particles


(b)   Give an equation that represents – decay, using quarks in the equation rather than
      nucleons.

      .....................................................................................................................................

      .....................................................................................................................................
                                                                                                                                                    (2)



(c)   (i)       Which fundamental force is responsible for electron capture?

                ...........................................................................................................................

      (ii)      What type of particle is an electron?

                ...........................................................................................................................

      (iii)     State the other fundamental forces that electrons may experience.

                ...........................................................................................................................
                                                                                                                                                    (3)
                                                                                                                                        (Total 9 marks)




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