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Ch 34 Take-Home Quiz

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					                                                                     Name ___________________________________
                                                                     Chapter 34 Electric Current Take-Home Quiz
                                                                     Mrs. Corey Conceptual Physics Period_________
                                                                     Due Date: Tues, May 3, 2011

Multiple Choice (Write          the letter of the correct answer in the blank)

_______ 1. In order for there to be a flow of charge from one place to another, there must be ______.
a) a voltage difference between the two places                  c) a color difference between the two places
b) a resistance difference between the two places               d) a volume difference between the two places

_______ 2. In solid conductors (metals), electric current is the flow of ____________.
a) positive and negative charges                 c) neutrons
b) electrons                                     d) protons

_______ 3. An ampere is a ________________.
a) unit of current    b) unit of charge     c) unit of voltage               d) unit of resistance

_______ 4. An example of a voltage source is
a) a resistor    b) a diode       c) a battery         d) a capacitor

_______ 5. Compared to thin wires, electrical resistance in thick wires is
a) greater           b) less              c) the same

_______ 6. Electrical resistance is measured in ________________.
a) volts       b) amperes               c) joules          d) watts               e) ohms

_______ 7. A not-so-bright Leonardtown High School student receives an electric shock when she touches a live
electrical wire. The electrons in the current come from _____________.
a) the student’s body                            c) the ground
b) a nearby power supply                         d) the object causing the shock

_______ 8. The primary reason that a bird can perch harmlessly on bare high voltage wires is that ____.
a) a bird has a very large electrical resistance.
b) there is no potential difference across the bird’s feet.
c) a bird’s feet are on different wires.
d) the bird is wearing rubber shoes.

_______ 9. Alternating current is made by _______________.
a) huge chemical batteries      b) alternating current and voltage           c) a generator at a power company

_______ 10. The frequency of AC current in North America is ___________.
a) 120 V      b) 60 cycles per second        c) 30 V          d) 50 cycles per second

_______ 11. Current from a battery is always __________.
a) DC         b) AC

_______ 12. The resistance of your dry skin is _____________.
a) the same as wet skin        b) more than wet skin          c) less than wet skin

_______ 13. Electric power is defined as ______________.
a) current times voltage               b) current divided by voltage
c) voltage divided by current          d) resistance times voltage
_______ 14. Power outlets in our homes typically tend to have a potential difference of _______.
a) 240 V      b) 120 A        c) 120 V       d) 60 A          e) 30 V

_______ 15. A 12-V battery is connected to a resistor and 0.2 A of current flows in the resistor. What is the resistance
of the resistor?
a) 12           b) 0.2      c) 2.4         d) 0.0167  e) 60 

_______ 16. The current through a 10-ohm resistor connected to a 120-V power supply is ______.
a) 0.083 A    b) 120 A       c) 12 A         d) 1200 A              e) 10 A

_______ 17. A 10-ohm resistor has a 5-A current in it. What is the voltage across the resistor?
a) 0.5 V             b) 2 V           c) 5 V           d) 10 V          e) 50 V

_______ 18. Calculate the current where 50 coulombs of charge pass a point in 10 seconds.
a) 5 A        b) 50 A         c) 500 A       d) 0.5 A       e) 0.2 A

_______ 19. How much power is used by a 6.0-V flashlight battery that draws 0.5 A of current?
a) 30 W       b) 6 W       c) 3 W           d) 12 W          e) 0.5 W

_______ 20. An 1800 W toaster plugged into a 120-V wall outlet uses how much current?
a) 216,000 A      b) 1800 A         c) 120 A        d) 15 A          e) 0.067 A

________ 21. A 60-Watt light bulb and a 100-Watt light bulb are each rated at 120 V. Which light bulb has the larger
resistance?
a) the 60-W bulb     b) the 100-Watt bulb              c) Both have the same resistance

________ 22. An electric heater is rated at 300 W for use in a 110-V circuit. The safety fuse in the circuit can handle
15A of current. How many heaters can be safely operated in the circuit?
a) 2            b) 3          c) 4              d) 5            e) 6

________ 23. A kilowatt-hour measures:
a) power      b) temperature        c) charge            d) resistance            e) energy

_______ 24. If someone near you receives an electric shock, you should _______.
a) call 911 and try to shut off the power supply
b) grab a cell phone and use it to push the person away from the power supply
c) gab the person being shocked and yank them away from the power supply
d) text your other friend to tell them

_______ 25. Which device acts as a one-way valve to allow electricity to flow in one direction only?
   a) Diode          b) capacitor             c) resistor               d) generator

_______26. What is the purpose of the third prong of an electrical plug?
   a) To hold onto better
   b) Safety: to allow excess electric charge to pass safely to the ground
   c) It looks better
   d) To provide a potential difference so current can flow.

_______ 27. If a person uses their 15 Watt iPod for 3 hours, how much energy is used?
   a) 15 watt-hours            b) 3 Watt-hours          c) 45 Watt-hours       d) 5 Watt-hours

				
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