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```					GCE 2008 with Edexcel
AL Physics consists of 6 Units

•   Unit 1: Physics on the go
•   Unit 2: Physics at work
•   Unit 3: Exploring physics
•   Unit 4: Physics on the move
•   Unit 5: Physics from creation to collapse
•   Unit 6: Experimental physics
The ‘theory’ units
Unit 1: Physics on the go      Unit 4: Physics on the move
Unit 2: Physics at work        Unit 5: Physics from creation to
collapse

• Assessed by written paper    • Assessed by written paper
• 1 hour 30 minutes            • 1 hour 30 minutes
• 80 marks                     • 80 marks
• multiple choice questions,   • multiple choice questions,
short questions and long       fewer short questions and
questions                      more long questions
• 40% of the AS marks          • 40% of the A2 marks
• 20% of the A level marks     • 20% of the A level marks
Multiple choice questions

•   Wider specification coverage than before
•   Only worth 10 marks from 80
•   Do not spend too much time
•   Do these at the end?
•   Do not leave any blank
Appendix 12 – page 179
General and mathematical requirements
•   Physical quantities and their units
•   Significant figures
•   Order of magnitude
•   Rate of change
•   Vectors and scalars
•   Graphs
•   Arithmetic and computation
•   Algebra
•   Geometry and trigonometry
Physical quantities and their units

• Understand the distinction between base and derived
physical quantities and their S.I. Units.

The base physical quantities:
mass, length, time, electric current, temperature, amount
of substance

The base units:
kilogram, metre, second, ampere, kelvin, mole
Examples of questions

Unit 1, Q3
Which of these units is the same as the newton?
 A kg m s–1
 B kg m s–2
 C kg m2 s–2
 D kg m2 s–3

Examples of questions

Unit 2, Q 13(a)
What is the coulomb in base units?

Charge = current x time
So a coulomb is an Amp second or A s
Examples of questions

Unit 2, Q 15(b)
The current I in a length of aluminium of cross sectional area A
is given by the formula
I = nev A
Where is the charge on an electron.
Show that the units on the left hand side of the equation are
consistent with those on the right hand side.
A = m–3 A s m s–1 m2
A = m–3 m m2 s s–1
A=A
Here are three physical quantities.
Work out the base unit for each quantity.

•   The Plank constant = 6.63 x 10-34 J s
•   kg m2 s-1
•   Permittivity of space = 8.85 x 10-12 C V-1 m-1
•   A2 kg-1 m-3 s4
•   Coulomb law constant = 8.99 x 109 N m2 C-2
•   kg m3 A-2 s-4
Units
• Every value that is calculated must have a unit or the mark
will be lost.

• In ‘show that’ questions the unit will be given.

• ‘Show that’ questions are used so that if students cannot do an
early part of a questions they can use the given value to do
later parts of the question.

• In a ‘show that’ question students need to give one more
significant figure than the value given.
Examples of questions

Unit 1, Q 11(a)
The Saturn V rocket used in NASA’s space programme had a
mass of 3.04 × 106 kg.
It took off vertically with a thrust force of
3.40 × 107N.
(a) Show that the resultant force on the rocket is
about 4 × 106 N.
resultant   force =   upward force – weight
resultant   force =   upward force – mg
resultant   force =   3.40 × 107– 3.04 × 106 x 9.81
resultant   force =   4.2 × 106 N
Orders of magnitude
• Appreciate the order of magnitude of common physical
quantities.
mass of a man?
70 kg
height of a man?
1.8 m
mass of a car?
1000 kg
volume of the room?
?????
speed of a sprinter?
10 m/s
characters on the page of a book?
(60 characters per line, 40 lines per page, 2 400 characters per
page [6754 Jan ‘09])
Orders of magnitude

• Make order of magnitude calculations.

Check that the answer to a calculation makes sense.
Beware of impossible answers e.g. photoelectrons moving
faster than the speed of light.
Graphs

• plotting graphs

• ‘line of best fit’

• y = mx + c

• area under a graph
Familiarity with graphs

• Direct proportionality
y = kx        must go through (0,0)
• Inverse proportionality
y = k/x       check values of xy
• Inverse square laws
y = k/X2      check values of x2 y
Examples of questions

Unit 1 Q9
Velocity can be found from the
 A area under a displacement-time graph
 B area under a force-time graph
 C gradient of a displacement-time graph
 D gradient of an acceleration-time graph


Examples of questions

Unit 1 Q19
This question requires students to:
• recognise proportionality from a straight line graph
• find the gradient of the graph
• calculate the area under the graph.
Examples of questions

Unit 2 Q22
This question requires students to:
• plot points on a graph
• draw a line (curve) of best fit
• sketch a graph, given the axes.
Examples of questions
PHY5 June 09

This question required students to
show inverse square relationship
find an area under a graph
Unit 3: Exploring physics

• For international centres this will be assessed by written
paper.

• This paper aims to test knowledge of practical techniques
without having to do a practical assessment.
Unit 3: Exploring physics

The international alternative to internal assessment:
• 1 hour 20 minutes
• 40 marks
• Multiple choice questions, short questions and long questions
• 20% of the total AS marks
• 10% of the total A level marks
Practicals

• Suggested practicals for students to carry out are given
in the specification.

• Students may be asked to describe an experiment in
Unit 1 or Unit 2 as well as unit 3.

• Any appropriate method will gain marks.
Students should be able to:
•   draw labelled diagrams of apparatus
•   draw circuit diagrams
•   state what measurements you would take
•   describe how to obtain accurate results
•   describe safety precautions
•   identify possible sources of error
•   calculate absolute and percentage errors
•   criticise sets of measurements
•   plan experiments
•   plot graphs
•   do calculations
•   calculate the mean of a set of data
Examples of questions
Unit 1 Q15

You are asked to determine the acceleration of free fall at the
surface of the Earth, g, using a free fall method in the
laboratory.

Describe the apparatus you would use, the measurements you
would take and explain how you would use them to
determine g.

Give one precaution you would take to ensure the accuracy of
•   Ball bearing held by electromagnet
•   Break circuit to start timer.
•   Ball falls to break circuit to stop timer.
•   Labelled diagram of apparatus.
•   Time, t, recorded on electronic timer.
•   Distance fallen, s, measured on metre rule.
•   Repeat for 6 different values of s.
•   s = ut + ½ at2
•   s = ½ gt2
•   Plot graph of s (y axis) against t2 (x axis)
•   Gradient = ½ g
•   g = 2 x gradient
Examples of questions
Unit 1 Q19 (d)

The student uses a camera to video the movement of the toy in front
of a metre rule. The video is then used to find the maximum height
reached by the toy.

(i) Explain the advantage of using the video camera over making
observations just by eye.

(ii) The student repeats this procedure several times and records the
following data:

0.45 m, 0.44 m, 0.36 m, 0.46 m, 0.45 m.
mean maximum height = 0.45 m
Why is the student justified in using 0.45 m as the mean?

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 views: 11 posted: 7/27/2012 language: English pages: 34