Deck 15: Magnetism and Electromagnetism

Question 1

If the coercive force is large, the magnet is difficult to ____.

A)demagnetize
B)stabilize
C)magnetize
D)polarize

Answer 1

A

Question 2

The permeability of nonmagnetic materials, such as wood, aluminum, and plastic, is the same as the permeability of a vacuum (or air).

Answer 2

True

Question 3

Magnetic lines of force, often referred to as ____ lines, do not cross each other.

A)force
B)flux
C)repulsion
D)static

Answer 3

B

Question 4

A hysteresis loop is the kind of loop generated when alternating current (AC) is applied to the coil.

Question 5

The amount of residual magnetism depends on the ____ of the steel used.

A)polarity
B)charge
C)lamination
D)retentivity

Question 6

A ____ magnet will keep its strength after the magnetizing force is removed; that is, the magnet maintains its orderly atomic arrangement.

A)temporary
B)strong
C)weak
D)permanent

Question 7

The presence of ____ materials in the DC magnet coil has no appreciable effect on its magnetic force.

A)magnetic
B)polar
C)dense
D)nonmagnetic

Question 8

Malleability is the number of times that the flux density is increased by the addition of the magnetic material.

Question 9

____ substances have permeability ratings slightly greater than that of air.

A)Magnetic
B)Diamagnetic
C)Paramagnetic
D)Duomagnetic

Question 10

Alnico 7 is presently the most frequently used permanent magnet material.

Question 11

Magnetism is the same force as the attraction and repulsion forces caused by static electrical charges.

Question 12

To demagnetize an object, place the object into a varying magnetic field powered by a source of direct current.

Question 13

All magnetism is essentially electromagnetic in origin.

Question 14

Flux equals magnetomotive force divided by reluctance.

Question 15

Iron, nickel, cobalt, and some oxides and alloys are called ferromagnetic materials.

Question 16

____ is when all of the atoms are facing in the same direction, and the magnet achieves its maximum strength.

A)Maturation
B)Maximization
C)Saturation
D)Finalization

Question 17

The force of the magnet is strongest at two areas on the magnet called the ____.

A)poles
B)spectrums
C)endpoints
D)currents

Question 18

Magnets for DC vibrators, motors, and generators and for AC equipment are an assembly of thin sheets of iron called ____.

A)ferromagnets
B)ferrolayers
C)cupric laminations
D)laminations

Question 19

The flux density is expressed either in teslas, gausses, or ____ per square inch.

A)webers
B)lines
C)maxwells
D)wells

Question 20

When a wire is wound into the form of a coil, each turn of wire is surrounded by its own circular magnetic field.