Test 4: Lesson 3. Solving Power Calculations
Each kilowatt-hour is equal to 100 watt-hours. True or False?
False
The unit of measurement of electrical power is the volt. True or False?
False
What formula can be used to find the current in a circuit if the power and resistance of the circuit are known?
I = square root or P/R
? is one of the equations used to find power.
P = E x I
Any time current flows through a resistance, heat is produced. True or False?
True
Power is consumed when a voltage is applied to a circuit and current flows through the load. True or False?
True
Power is the rate at which work is done. True or False?
True
Resistors have a power rating in watts that should not be exceeded, or the resistor will be damaged. True or False?
True
The joule is a unit of energy used to measure the heat or work produced or consumed in a system. True or False?
True
The work used in a heating circuit is called lost work because it cannot be used to move anything. True or False?
True
When the current is doubled in a circuit, the power will increase to four times its original value. True or False?
True
Work is the product of the force and the distance that force moves something, and is measured in ? . a. foot-pounds b. horsepower c. time d. weight
a. foot-pounds
If one watt is equal to 0.00134 horsepower, then one kilowatt equals ? . a. 0.134 hp b. 1.34 hp c. 13.4 hp d. 134 hp
b. 1.34 hp
A resistor draws 12 amperes and has a resistance of 10 ohms. How much power, in kilowatts, is consumed? a. 0.144 kW b. 1.44 kW c. 14.4 kW d. 144 kW
b. 1.44 kW
If 13,800 volts is delivered to a circuit that has a resistance of two ohms, how much power, in megawatts, is consumed in the load? a. 0.003450 MW b. 95.22 MW c. 380.88 MW d. 952.20 MW
b. 95.22 MW
If the voltage and resistance of a circuit is known, what equation is used to find power? a. P = I^2 x R b. P = E^2/R c. P = R/E^2 d. P = E^2R
b. P = E^2/R
One ? is equal to 33,000 foot-pounds per minute. a. ampere b. horsepower c. kilovolt d. kilowatt
b. horsepower
The ? in an electrical circuit uses the power to convert electrical energy into some other form of energy. a. amperes b. load c. ohms d. voltage
b. load
A 50-ohm device draws five amperes. What is its load in kilowatts? a. 0.010 kW b. 0.250 kW c. 1.25 kW d. 12.5 kW
c. 1.25 kW
In addition to I^2R (power) losses, a five-horsepower motor uses ? of electrical power. a. 3,235 W b. 3,370 W c. 3,730 W d. 3,820 W
c. 3,730 W
A 1,000-watt lamp operates on 120 volts. How much current does it draw? a. 833 mA b. 1,200 mA c. 8.33 A d. 83.3 A
c. 8.33 A
A certain device operates on 12 volts and draws seven amperes. How much power does it consume? a. 0.58 W b. 1.71 W c. 84 W d. 588 W
c. 84 W
I^2R loss is often called ? . a. counter electromotive force (CEMF) b. electromagnetism c. heat loss d. hysteresis
c. heat loss
Electrical energy must be changed or converted to some other form of energy before there can be ? or watts. a. electromotive force (EMF) b. frequency modulation c. power d. voltage
c. power
A 2,000-watt circuit draws 0.833 amperes. What is its rated voltage? a. 4,160 mV b. 240 V c. 1,666 V d. 2,400 V
d. 2,400 V
A 50-ohm device draws 10 amperes. What is its load in kilowatts? a. 2 kW b. 5 kW c. 20 kW d. 50 kW
d. 50 kW
If the current and resistance of a circuit is known, what equation is used to find power? a. P = I^2/R b. P = R^2/I c. P = I x R d. P = I^2 x R
d. P = I^2 x R
Potential energy is measured in volts, and the unit of power is the ? . a. ampere b. hertz c. joule d. watt
d. watt
One horsepower is equal to 746 ? . a. foot-pounds b. joules c. volts d. watts
d. watts
