Deck 10: Magnetic Induction

Question 1

Iron core inductors cannot be used for ____________________-frequency applications because of eddy current loss and hysteresis loss in the core material.

Answer 1

high

Question 2

A coil has an inductance of one ____ when a current change of one ampere per second results in an induced voltage of one volt.

A) coulomb
B) fleming
C) henry
D) weber

Answer 2

C

Question 3

The principle of _________________________ states that whenever a conductor cuts through magnetic lines of flux, a voltage is induced into the conductor.

Answer 3

magnetic induction

Question 4

An exponential curve shows the rate at which current increases or decreases in a(n) ____.

A) conductor
B) inductor
C) insulator
D) resistor

Question 5

When using Fleming's generator rule, the thumb points in the direction of the ____.

A) current induced into the armature
B) thrust
C) field flux

Question 6

A device used to prevent induced voltage spikes when the current flow through an inductor is stopped is the ____________________.

Question 7

Most AC generators and alternators operate on the principle of the ____________________ being stationary while a ____________________ is moved through the coil.

Question 8

A coil wound on a core made of magnetic material such as silicon steel or soft iron is referred to as a(n) ____ inductor.

A) shorted
B) donut
C) iron core
D) conducting

Question 9

____ law states that an induced voltage or current opposes the motion that causes it.

A) Henry's
B) Lenz's
C) Fleming's
D) Weber's

Question 10

The induced ____________________ is proportional to the rate of change of current.

Question 11

Fleming's ____________________ generator rule can be used to determine the relationship of the motion of the conductor in the magnetic field to the direction of the induced current.

Question 12

When using Fleming's generator rule, the forefinger points in the direction of the ____.

A) current induced into the armature
B) thrust
C) field flux

Question 13

The exponential curve describes a rate of certain occurrences and is divided into ____ time constraints.

A) 3
B) 5
C) 7
D) 9

Question 14

The standard measure of inductance is the ____.

A) frank
B) henry
C) lenz
D) none of the above

Question 15

The polarity of the ____ voltage is determined by the polarity of the magnetic field in relation to the direction of movement.

A) applied
B) induced
C) linear
D) DC

Question 16

There are three factors that determine the amount of ____________________ that will be induced in a conductor. They are the number of turns of wire, the strength of the magnetic field, and the speed of the cutting action.

Question 17

A coil wound on a nonmagnetic core material such as wood or plastic is referred to as a(n) ____ inductor.

A) donut
B) open
C) insulated
D) air core

Question 18

When using Fleming's generator rule, the center finger shows the direction of the ____.

A) current induced into the armature
B) thrust
C) field flux

Question 19

While inductance is proportional to the number of turns of wire, the type of core material used, and the cross-sectional area of the core, it is inversely proportional to the core ____.

A) area
B) diameter
C) length
D) radius

Question 20

In magnetic measurement, 100,000,000 lines of magnetic flux are equal to one ____.

A) coulomb
B) henry
C) fleming
D) weber

Question 21

One of the basic laws of electricity is that whenever current flows through a conductor, a _________________________ is created around the conductor.

Question 22

A diode permits current to flow in ____________________ direction(s).

Question 23

A device that can be used for voltage spike suppression in either AC or DC circuits is the _________________________ varistor.

Question 24

A large amount of voltage that exists for a very short period of time is called a voltage ____________________.

Question 25

Metal oxide varistors are often found in _________________________ used to protect many home appliances such as televisions, stereos, and computers.