Module 4

Question 1

electricity that changes direction at a regular rate

Answer 1

Alternating Current

Question 2

property of a coil of wire that opposes any change in current

Answer 2

Inductance

Question 3

unit of inductance

Answer 3

Henry

Question 4

opposition to the flow of current in an ac circuit, due to inductance in the circuit

Answer 4

Inductive reactance

Question 5

property of a capacitor that opposes any change in potential difference between two points

Answer 5

Capacitance

Question 6

unit of capacitance

Answer 6

Farad

Question 7

opposition to the flow of current in an ac circuit, due to capacitance in the circuit

Answer 7

Capacitive reactance

Question 8

sum of inductive reactance, capacitive reactance, and resistance in a circuit

Answer 8

Impedance

Question 9

In _____, both the potential difference and the current change direction at a regular rate.

Answer 9

Alternating current

Question 10

In the United States and Canada, the standard alternating rate for electric power is _____.

Answer 10

60 Hertz

Question 11

Power companies use ac generators instead of dc generators, because ac can be sent over long distances at _____.

Answer 11

Low cost

Question 12

What device changes alternating current to a different combination of potential difference and current?

Answer 12

Transformer

Question 13

How does the power going into a transformer compare to the power coming out?

Answer 13

They are equal

Question 14

What values should you use when making calculations involving alternating current?

Answer 14

Effective values

Question 15

One complete electrical cycle equals _____ electrical degrees.

Answer 15

360

Question 16

The frequency of electricity generated depends on the number of ______ in the generator.

Answer 16

Magnetic poles

Question 17

What is the name of the property of a coil of wire that opposes any change in the current in the coil?

Answer 17

Inductance

Question 18

When the current changes continuously, as in an ac circuit, the _____ around the conductor also changes continuously.

Answer 18

Magnetic field

Question 19

Lenz’s law says that the induced potential difference always _____ the effect that produced it.

Answer 19

Opposes

Question 20

What is the unit of measurement for inductance?

Answer 20

The henry

Question 21

When an inductor opposes changes in the current in an ac circuit, the opposition is called _____.

Answer 21

Inductive reactance

Question 22

Does capacitance in an ac circuit cause the current to lead or lag the potential difference?

Answer 22

Lead

Question 23

What is the unit of measurement for capacitive reactance?

Answer 23

Ohms

Question 24

The ratio of the average power to the in-phase power is called the _____.

Answer 24

Power factor