Quizzes

Question 1

Where are the forces of a magnet the strongest?

Answer 1

At the poles

Question 2

What was the first compass made out of?

Answer 2

magnetite, wood, water

Question 3

The North pole of a compass is the _____ ______ pole of the earth

Answer 3

magnetic south

Question 4

Three basic types of magnets?

Answer 4

Natural
Artificial
Electromagnets

Question 5

What magnets are man-made?

Answer 5

Artificial, Electromagnets

Question 6

Magnetic materials that are easily magnetized?

Answer 6

ferromagnetic

Question 7

Metals that are not as easily magnetized?

Answer 7

Paramagnetic

Question 8

Metals or non-metals that cannot be magnetized?

Answer 8

diamagnetic

Question 9

Four characteristics of flux lines?

Answer 9

• always complete a loop
• never cross
• have no insulator
• more dense closer to the conductor

Question 10

When will there be a magnetic field around a conductor?

Answer 10

When there’s current flow

Question 11

Formula for finding force between parallel conductors?

Answer 11

Fm= k x I1x I2 /d2

Question 12

A spiral shaped coil is called?

Answer 12

a helix

Question 13

A helically wound coil that produces a strong magnetic field is called?

Answer 13

A solenoid

Question 14

What 4 factors affect the strength of an electromagnet?

Answer 14

• number of turns
• core material
• spacing between
• vary current through the coil

Question 15

What is the device called that must be used to store a horseshoe magnet?

Answer 15

Keeper

Question 16

Which direction do magnetic lines of force flow (outside the magnet)

Answer 16

North to South

Question 17

The property that opposes the setting up of flux lines is called?

Answer 17

Reluctance

Question 18

What type of material would you use to make a magnetic screen?

Answer 18

soft iron

Question 19

When would magnetic lines of force repel each other?

Answer 19

When facing opposite

Question 20

When would magnetic lines of force attract each other?

Answer 20

When facing each other

Question 21

Name three ways to produce artificial magnets?

Answer 21

• DC current
• tapping or vibrating
• stroking with a magnet

Question 22

What is permeability?

Answer 22

The ease of setting up flux lines

Question 23

What do we use to determine the permeability?

Answer 23

BH graph

Question 24

What is it called when all of the domains are aligned with the magnetic field?

Answer 24

saturation

Question 25

What is the difference between “theoretical saturation” and “practical saturation”?

Answer 25

Theoretical - all domains perfectly arranged Practical - When domains are almost aligned and it is not practical to align them perfectly

Question 26

What is the point called in which the flux density has hit practical saturation?

Answer 26

Knee

Question 27

The magnetizing curve that is plotted on the graph is called?

Answer 27

hysteresis loop

Question 28

What is residual magnetism?

Answer 28

the amount of flux density that remains in the material

Question 29

What is coercive force?

Answer 29

Amount of force to remove the residual magnetism

Question 30

Which one would have greater flux? (Iron core or Air core)

Answer 30

Iron core

Question 31

AC magnetic cores are usually made from high ___________________ and low _____________?

Answer 31

electrical resistance | retentivity

Question 32

What determines polarity of an electromagnet?

Answer 32

power source

Question 33

By increasing the current the ___________________ would increase as well?

Answer 33

MMF