PHEP 15

Question 1

Describe flux density? (think measurement)

Answer 1

Its the amount of flux per unit area

Question 2

The strength of the magnetic field depends largely on?

Answer 2

The material involved and the extent to which the material has been magnetized.

Question 3

What produces the strongest artificial magnets?

Answer 3

Induced Magnetism (Electromagnets)

Question 4

Magnetism is a ______.

Answer 4

Force

Question 5

What are the three important facts about force lines?

Answer 5

no lines cross
all lines are complete
all lines leave the magnet at right angles to the magnet.

Question 6

What can be done to build a stronger magnetic field?

Answer 6

Add one or more turns of wire.

Question 7

What happens when a conductor is moved through a magnetic field?

Answer 7

A voltage is induced in the conductor.

Question 8

The direction of current flow depends on?

Answer 8

The direction of flux cutting and the direction of the magnetic field.

Question 9

State Lenz’s Law

Answer 9

In all cases of Electromagnetic induction, all induced EMF’s counter the motion producing the EMF.
Or more simply, for every force there is a counter force set up which tends to oppose the first force.

Question 10

Reluctance in a _____ circuit corresponds to ______ in an electric circuit.

Answer 10

magnetic

resistance

Question 11

Total flux divided by cross-sectional area gives you?

Answer 11

The flux density.

Question 12

The amount of flux is measured by the number of lines, called ________.

Answer 12

Maxwells

Question 13

How many magnetic fields are involved when discussing induced magnetism?

Answer 13

Two
magnetic field
conductor field

Question 14

What direction are the fields traveling in when discussing induced magnetism?

Answer 14

The magnetic field travels in a straight line form the North to South poles.
The conductor field is a circular field surrounding the conductor.

Question 15

Permeability corresponds to _______ in an electric circuit.

Answer 15

Conductivity

Question 16

Permeability is a measurement of?

Answer 16

The relative ability of a material to carry flux.

Question 17

Permeability is inversely proportional to?

Answer 17

Flux density.

Question 18

Describe why Iron flux density can no longer increase after as the amp turns are continually increased?

Answer 18

Because the permeability of the Iron as decreased due to saturation.

Question 19

What can be done to increase the flux density of a material after it’s become saturated?

Answer 19

Nothing.

Question 20

When turns of a conductor are wound about an Iron core, an ___________ results.

Answer 20

Electro-magnet.

Question 21

Induction is the process of generating an?

Answer 21

Electrical voltage in a conductor.

Question 22

Mutual Induction is the transfer of electrical energy from one ______ to ______.

Answer 22

coil or circuit
to
another coil or circuit

Question 23

What is inductance?

Answer 23

The ability of a coil or circuit to produce a counter-voltage within itself by self-induction.

Question 24

What determines a coil’s inductance?

Answer 24

The length
The number of turns
The diameter, and
The permeability of the core.

Question 25

Inductance is measured in ________.

Answer 25

Henries.

Question 26

Induction is a _________, inductance is an _______, and inductive reactance is a ________.

Answer 26

Process
Ability
Quantity

Question 27

The driving force causing a magnetic filed is known as?

Answer 27

Magneto-motive force