Page 41 - Teach Yourself Electricity and Electronics

Quiz 21

11. Movement of holes in a semiconductor:
A. Is like a flow of electrons in the same direction.
B. Is possible only if the current is high enough.
C. Results in a certain amount of electric current.
D. Causes the material to stop conducting.
12. If a material has low resistance:
A. It is a good conductor.
B. It is a poor conductor.
C. The current flows mainly in the form of holes.
D. Current can flow only in one direction.
13. A coulomb:
A. Represents a current of one ampere.
B. Flows through a 100-watt light bulb.
C. Is one ampere per second.
D. Is an extremely large number of charge carriers.

14. A stroke of lightning:
A. Is caused by a movement of holes in an insulator.
B. Has a very low current.
C. Is a discharge of static electricity.
D. Builds up between clouds.
15. The volt is the standard unit of:
A. Current.
B. Charge.
C. Electromotive force.
D. Resistance.
16. If an EMF of one volt is placed across a resistance of two ohms, then the
current is:
A. Half an ampere.
B. One ampere.
C. Two amperes.
D. One ohm.
17. A backwards-working electric motor is best described as:
A. An inefficient, energy-wasting device.
B. A motor with the voltage connected the wrong way.
C. An electric generator.
D. A magnetic-field generator.