AC Electrical Quiz 2

Question 0

What two ways can you look at inductance?

Answer 0

Electrical inertia

Energy stored in an electromagnetic field

Question 1

What is inductance?

Answer 1

The property of electricity that opposes any change in current due to a change in the electromagnetic field caused by the current

Question 2

As current increases, what happens to the flux field?

Answer 2

It increases

Question 3

As current decreases, what happens to the flux field?

Answer 3

It decreases.

Question 4

If current flow reverses?

Answer 4

The flux field also reverses

Question 5

Lenz’s Law?

Answer 5

The voltage that is induced into a conductor by a change in the flux field is caused by a change in the current. It is of such a polarity that it opposes the current change which is caused by the change in the flux field

Question 6

How is inductance measured?

Answer 6

In henries.

Question 7

What factors affect inductance in an inductor?

Answer 7

Number of wraps in the coil 
Length of the coil 
Width of the coil 
Type of core 
Total inductance in a circuit

Question 8

How is total inductance in a series circuit found?

Answer 8

By adding all of the inductors

Question 9

How is total inductance found in a parallel circuit?

Answer 9

By the inverse sum of the inverses

Question 10

When will inductance in DC occur?

Answer 10

When the circuit is first closed, when the circuit is first opened, the instant current changes.

Question 11

What is the only purpose of inductance in DC?

Answer 11

To control the amount of time it takes for total current to flow when the circuit is first closed , or stop when the circuit is first opened.

Question 12

What is one time constant defined as?

Answer 12

The amount of time it takes in seconds, for 63.2% of the total current to begin to flow in a circuit

Question 13

How many time constants does it take for total current to flow in a circuit?

Answer 13

Five time constants

Question 14

Time constant formula?

Answer 14

L/R x5

Question 15

Does an inductor cause current to lead or lag voltage?

Answer 15

Lag

Question 16

What is inductive reactance?

Answer 16

The actual opposition to current flow produced by inductance

Question 17

Formula for inductive reactance?

Answer 17

XL= 2 pi f l

Question 18

What is the use of a transformer?

Answer 18

To change values of current and voltage

Question 19

What principle do transformers use?

Answer 19

Mutual inductance

Question 20

Two forms of transformer based on voltage?

Answer 20

Step up and step down

Question 21

Form of transformer is based on what?

Answer 21

Ratio of primary windings to secondary windings

Question 22

What is capacitance?

Answer 22

Energy stored in an electrostatic field

Question 23

What is a capacitor?

Answer 23

A device designed to produce capacitance

Question 24

What is a capacitor made up of?

Answer 24

Two conductive plates, separated by an insulator called a dielectric

Question 25

Factors effecting capacitance?

Answer 25

Area of the plates Distance between the plates Dielectric material

Question 26

Total capacitance in a series circuit?

Answer 26

Inverse sum of the inverses

Question 27

Total capacitance in parallel?

Answer 27

Sum of the individual capacitors.

Question 28

Time constant formula for capacitance?

Answer 28

RxC

Question 29

Formula for capacitive reactance?

Answer 29

Xc= 1 ------ 2pifC

Question 30

Applications of capacitive reactance?

Answer 30

Used to store high energy in DC Fuel gauge sending units Used to absorb static Used to bring current and voltage back into phase

Question 31

Types of capacitors?

Answer 31

Non electrolytic Electrolytic Fixed and variable