C1 Electric Circuits (Current, Resistance, Power) Chapter 17

On-Line Quiz - 300 points

25 questions worth 12 points each

 

1.  Electric resistance has units of:

    a. ohm

    b. (W-m)-1

    c. ampere

    d. volt-ampere

    e. (oC) -1

    f. W-m

 

2.  Conductivity has units of:

    a. ohm

    b. (W-m) -1

    c. ampere

    d. volt-ampere

    e. (oC) -1

    f. W-m

 

3.  Temperature coefficient of resistivity has units of:

    a. ohm

    b. (W-m) -1

    c. ampere

    d. volt-ampere

    e. (oC) -1

    f. W-m

 

4.  Electric current has units of:

    a. ohm

    b. (W-m) -1

    c. ampere

    d. volt-ampere

    e. (oC) -1

    f. W-m

 

5.  Resistivity has units of:

    a. ohm

    b. (W-m) -1

    c. ampere

    d. volt-ampere

    e. (oC) -1

    f. W-m

 


Page 2

 

6.  Electric power has units of:

    a. ohm

    b. (W-m) -1

    c. ampere

    d. volt-ampere

    e. (oC) -1

    f. W-m

 

7.  A car battery

    a. has an emf of 6 V consisting of one 6-V cell.

    b. has an emf of 6 V consisting of three 2-V cells connected in series.

    c. has an emf of 6 V consisting of three 2-V cells connected in parallel.

    d. has an emf of 12 V consisting of six 2-V cells connected in series.

    e. has an emf of 12 V consisting of six 2-V cells connected in parallel.

 

8.  If you connect two identical storage batteries together in parallel, and place them in a circuit, the combination will provide

    a. twice the voltage and twice the total charge that one battery would.

    b. twice the voltage and the same total charge that one battery would.

    c. the same voltage and twice the total charge that one battery would.

    d. half the voltage and half the total charge that one battery would.

    e. half the voltage and twice the total charge that one battery would.

 

9.  If you connect two identical storage batteries together in series ("+" to "-"), and place them in a circuit, the combination will provide

    a. zero volts.

    b. twice the voltage, and different currents will flow through each.

    c. twice the voltage, and the same current will flow through each.

    d. the same voltage, and different currents will flow through each.

    e. the same voltage and the same current will flow through each.

 

10. The net direction in which electrons flow through a circuit is

    a. the conventional current

    b. opposite the conventional current

 

11. A coulomb per second is the same as

    a. a watt.

    b. an ampere.

    c. a volt-second.

    d. a volt per second.

 

12. A device obeying Ohm's law must have a resistance which

    a. is proportional to voltage

    b. is proportional to current

    c. is constant

    d. is zero

 


Page 3

 

13. Consider two copper wires.  One has twice the length and twice the cross-sectional area of the other.  How do the resistances of these two wires compare?

    a. Both wires have the same resistance.

    b. The longer wire has twice the resistance of the shorter wire.

    c. The longer wire has four times the resistance of the shorter wire.

    d. None of the above.

 

14. Negative temperature coefficients of resistivity

    a. do not exist.

    b. exist in conductors.

    c. exist in semiconductors.

    d. exist in superconductors.

 

 

15. Which of the above graphs indicates that the material is likely a semiconductor?

    a. graph A

    b. graph B

    c. graph C

    d. graph D

 

16. If the resistance in a constant voltage circuit is doubled, the power dissipated by that circuit will

    a. increase by a factor of two.

    b. increase by a factor of four.

    c. decrease to one-half its original value.

    d. decrease to one-fourth its original value.

 


Page 4

 

17. The resistivity of most common metals

    a. remains constant over wide temperature ranges.

    b. increases as the temperature increases.

    c. decreases as the temperature increases.

    d. varies randomly as the temperature increases.

 

 

18. In the graph shown, what physical quantity does the slope represent?

    a. Current

    b. Energy

    c. Resistivity

    d. Resistance

 

19. A 500-W device is connected to a 100-V power source.  What current flows through this source?

    a. 50,000 A

    b. 0.2 A

    c. 5 A

    d. None of the above

 

20. A lamp uses a 150-W bulb.  If it is used at 120 V, what current does it draw and what is its resistance?

 

21. Appliances in the USA are designed to work on 110-120 V, whereas appliances in Europe operate on 220-240 V.  What would happen if you tried to use a European electric shaver in this country?

    a. It would probably work as well as it does in Europe, since it is the power rating, not the voltage rating, that matters.

    b. It would probably work as well as it does in Europe, since it is the current rating, not the voltage rating, that matters.

    c. It would barely work (or maybe not work at all), since the voltage here is too low to push enough current through the device.

    d. It would probably overheat and burn up before very long.

    e. This question cannot be answered without knowing the frequency used in Europe and in the USA, since this is the parameter that matters most in any electrical device that operates on alternating current.

 


Page 5

 

22. A battery acquires and stores:

    a. charge

    b. potential

    c. energy

    d. all of the above

 

23. What do you buy from the "power" company?

    a. power

    b. potential

    c. current

    d. energy

 

24. A negative charge, if free, tries to move

    a. from high potential to low potential

    b. from low potential to high potential

    c. toward infinity

    d. away from infinity

 

25. Consider a current moving from left to right through a resistor.  Which end of the resistor is at higher potential?

    a. left

    b. right

    c. indeterminate depends if current is charging a battery or discharging a battery.