Electrical Power and Energy
1. An electrical appliance draws 9.0 amperes of current when
connected to a 120-volt source of potential difference.
What is the total amount of power dissipated by this
appliance?
(1) 13 W
(3) 130 W
(2) 110 W
(4) 1100 W
6. The heating element on an electric stove dissipates
4.0 × 102 watts of power when connected to a 120-volt
source. What is the electrical resistance of this heating
element?
(1) 0.028 Ω
(3) 3.3 Ω
(2) 0.60 Ω
(4) 36 Ω
2. In a series circuit containing two lamps, the battery supplies
a potential difference of 1.5 volts. If the current in the
circuit is 0.10 ampere, at what rate does the circuit use
energy?
(1) 0.015 W
(3) 1.5 W
(2) 0.15 W
(4) 15 W
7. As the resistance of a constant-voltage circuit is increased,
the power developed in the circuit
(1) decreases
(3) remains the same
(2) increases
3. One watt is equivalent to one
(1) N•m
(3) J•s
(2) N/m
(4) J/s
8. A 4.50-volt personal stereo uses 1950 joules of electrical
energy in one hour. What is the electrical resistance of the
personal stereo?
(1) 433 Ohms
(3) 37.4 Ohms
(2) 96.3 Ohms
(4) 0.623 Ohms
4. As the potential difference across a given resistor is
increased, the power expended in moving charge through
the resistor
(1) decreases
(3) remains the same
(2) increases
9. If 60. joules of work are required to move 5.0 coulombs of
charge between two points in an electric field, what is the
potential difference between these points?
(1) 5.0 V
(3) 60. V
(2) 12 V
(4) 300 V
5. While operating at 120 volts, an electric toaster has a
resistance of 15 ohms. The power used by the toaster is
(1) 8.0 W
(3) 960 W
(2) 120 W
(4) 1,800 W
10. A device operating at a potential difference of 1.5 volts
draws a current of 0.20 ampere. How much energy is used
by the device in 60. seconds?
(1) 4.5 J
(3) 12 J
(2) 8.0 J
(4) 18 J
11. How much electrical energy is required to move a 4.00microcoulomb charge through a potential difference of 36.0
volts?
(3) 1.44 × 10–4 J
(1) 9.00 × 106 J
(2) 144 J
(4) 1.11 × 10–7 J
Electrical Power and Energy
Answer Key
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