Chapter 7: Power
MULTIPLE CHOICE
1. The instantaneous rate at which work is done is called the ____.
a.
electric rate
c.
electric power rate
b.
power rate
d.
wattage rate
2. When work is done in a short period of time, the instantaneous power rate is ____ when the same
amount of work is done over a longer period of time.
a.
less than
c.
equally the same as
b.
greater than
d.
not enough information is given
3. The symbol ____ represents electrical power.
a.
P
c.
EP
b.
E
d.
PE
4. The relationship of power, current, and voltage may be expressed as follows ____.
a.
P=I/E
c.
P=2(IE)
b.
P=E/I
d.
P=IE
5. A 200-watt, 120-volt light bulb uses ____.
a.
0.6 amp
c.
16.7 amps
b.
1.67 amps
d.
24,000 amps
6. Calculate the missing value: P = 1000 W, E = ____, I = 20 A.
a.
0.02 V
c.
500 V
b.
50 V
d.
20,000 V
7. The power dissipated in a circuit is often less than ____ watt(s).
a.
1000
c.
10
b.
100
d.
1
8. One milliwatt = ____ watt.
a.
1/100
c.
1/10,000
b.
1/1,000
d.
1/100,000
9. One microwatt = ____ watt.
a.
1/1000
c.
1/100,000
b.
1/10,000
d.
1/1,000,000
10. Convert: 30 W = ____ mW.
a.
300
c.
30,000
b.
3,000
d.
300,000
COMPLETION
1. Power is directly proportional to both current and ____________________.
2. The basic unit of power is the ____________________.
3. _____________________ is an electrical force that creates current to flow into a closed circuit.
SHORT ANSWER
1. State the relationship of power, current and voltage.
2. Define power as it relates to electric circuits.