WorksheetsElectric Power
Total questions: 30
Worksheet time: 3hrs 30mins
Which one of the following quantities is equivalent to 1 W?
1 V/A
1 Ω • m
1 V • A
1 V/Ω
A kilowatt-hour is equivalent to
1000 W.
3600 J.
3,600,000 J/s.
3,600,000 J.
If the resistance in a constant voltage circuit is doubled, the power dissipated by that circuit will
increase by a factor of two.
increase by a factor of four.
decrease to one-half its original value.
decrease to one-fourth its original value.
If the voltage across a circuit of constant resistance is doubled, the power dissipated by that circuit will
be four times as large.
be two times as large.
decrease to one-half the original power.
decrease to one-fourth the original power.
What potential difference is required across an 8.0-Ω resistor to cause 2.0 A to flow through it?
4.0 V
16 V
8.0 V
32 V
A 4000-Ω resistor is connected across a 220-V power source. What current will flow through the resistor?
0.055 A
1.8 A
5.5 A
18 A
A resistor operated at 140 V dc is rated at 1.40 kW.
(a) What is the normal operating current through the resistor?
(b) What is the resistance of the resistor?
(a) 10 A . (b) 14 Ω
(a) 14 A . (b) 14 Ω
(a) 10 A . (b) 10 Ω
(a) 0.010 A . (b) 14000 Ω
An instrument is rated at 240 W if it is connected across a 120-V dc power supply.
(a) What current does it draw under normal operation?
(b) What is its resistance?
(a) 0.20 A (b) 360 Ω
(a) 60 A (b) 2.0 Ω
(a) 2.0 A (b) 60 Ω
(a) 0.2 A (b) 60 Ω
A 200-W light bulb is connected across a 100-V dc power supply. What current will flow through this bulb?
0.90 A
0.36 A
0.60 A
2.0 A
A 100-W light bulb is operated by a 110-V dc source. What is the resistance of this bulb?
100 Ω
8.0 × 10-3 Ω
120 Ω
240 Ω
A light bulb operating at a dc voltage of 100 V has a resistance of 200 Ω. How much power is dissipated in this bulb?
100 W
60 W
50 W
200 W
When 5.00 A is flowing through an 10.0-Ω device, how much power is being dissipated in the device?
50.0 W
250 W
500 W
2.50 kW
What is the resistance of a 0.100-kW light bulb designed to be used in a 120-V circuit dc?
12.0 Ω
144 Ω
1.2 Ω
0.83 Ω
How much energy does a 100-W light bulb use in 8.0 hours?
0.0080 kWh
0.80 kWh
13 kWh
800 kWh
What type of energy transfer is showed in the image
heat to light
electrical to sound
electrical to heat
heat to electrical
The picture shows what type of transformation
Electrical to mechanical
light to electric
electrical to light
light to light
Electrical Energy is all EXCEPT
Fireplace
blender
computer
tv
A computer uses what type of energy to operate?
Mechanical
Light
Electric
Sound
Electric power is the rate at which charge carriers
pass through an area
do work
move through a potential difference
collide with atoms
Which of the following equations is an equation for power, involving current and resistance?
P= I/V
P = IR
P = IVR2
P = I2R
Which of the following is an equation for power, involving voltage and resistance?
P = V/R
P = V2/R
P = VR
P = V2R2
If electrical power costs $0.12/kwh, and I use 9 x 108 Joules of electrical energy, what will I be charged?
$10
$20
$30
$40
Total energy = 350J
Useful energy = 70J
Workout the efficiency of this iphoneX.
efficiency = total energy inuseful energy ×100%
100%
80%
40%
20%
This car needs 8600J of energy to power it. If 5000J is changed into useful energy, how much energy is wasted?
13600J
3600J
5000J
8600J
