Deck 9: Electrical Power and Energy

Question 1

The efficiency of any device can be no greater than ____%.

A)85
B)90
C)99.9
D)100

Answer 1

D

Question 2

The words power and energy can be interchanged where measurement is concerned.

Answer 2

True

Question 3

The energy of the motion of a ball is called kinetic energy.

Answer 3

True

Question 4

Most common heating devices, such as toasters, irons, and electric ranges, are heated by current in a coil of ____ alloy wire or ribbon.

A)copper
B)silver
C)chromium
D)nickel-chromium

Question 5

The four letters ____ represent the unknown quantities in electrical power that may need to be found.

A)P, I, M, and E
B)I, M, E, and A
C)P, I, R, and E
D)I, M, R, and A

Question 6

One watt of power is dissipated (in the form of heat) when 1 volt of electrical pressure forces 1 ampere of current through the resistance of 1 ohm.

Question 7

A ____ is the energy needed to raise the temperature of 1 gram of water 1 degree Celsius.

A)joule
B)gram-joule
C)Btu
D)calorie

Question 8

Electrical energy is commercially sold in units called kilowatt-minutes.

Question 9

Another equation for electrical power is P equals ____ divided by R.

A)E-squared
B)E-cubed
C)I-squared
D)M-squared

Question 10

In general, energy can be converted from one form to another, and the efficiency of this energy conversion is a way of measuring how well the energy-converting device accomplishes its task.

Question 11

The lifting of a weight illustrates the meaning of a unit of measurement of energy.

Question 12

Energy indicates how fast power is used or produced.

Question 13

Because the unit joules per second is used so often, it is replaced with the single term ____.

A)watt
B)volt
C)amp
D)joules

Question 14

Work equals ____ times Distance.

A)Power
B)Force
C)Weight
D)Energy

Question 15

When a 20-pound weight is lifted 5 feet, it has 100 foot-pounds of potential energy that it did not have when it was on the ground.

Question 16

When James Watt started to sell steam engines, he found that an average horse, working at a steady rate, could do ____ foot-pounds of work per second.

A)425
B)550
C)1,250
D)3,200

Question 17

The following changes all require ____: mechanical movement, the production of heat or light, the production of sound, the conversion of one chemical compound into another, and the production of radio waves.

A)energy
B)measurement
C)joules
D)resistance heating

Question 18

James Watt compared the power of his steam engines to the amount of work an average team of horses could accomplish.

Question 19

The foot-pound is the energy unit commonly used in the American system of measurements.

Question 20

The electrical energy delivered to consumers is measured by an instrument known as the ____ meter.

A)kilowatt-minute
B)kilowatt
C)kilowatt-hour
D)k-minute