112 CHAP 1-4 NOTES

Question 1

Inverse square law
Force between two
magnetic fields _______
proportional to product of
their magnitudes and
_________ proportional to
square of distance between
them

Answer 1

directly; inversely

Question 2

permeability

Answer 2

The ease with which a material can be magnetized

Question 3

Methods to Induce a Current

Answer 3

1.Move the conductor through stationary
magnetic field

2.Move magnetic lines of force across conductor

3. Vary strength of stationary magnetic field
   through conductor

Question 4

Factors that effect the effectiveness of solenoids and electromagnets

Answer 4

diameter of the coil, its length, current passing along the coil.

Question 5

Electromagnetic Induction Required Components

Answer 5

• Magnetic field
• Conductor
• Relative motion

Question 6

Mutual Induction

Answer 6

• Two coils
• Varying current supplied to
  primary coil
• Induces current in secondary
  coil
• Two coils are electrically
  insulated from each other

Question 7

Generators

Answer 7

Convert mechanical to
electrical energy

Question 8

Slip Rings and Brushes function

Answer 8

• Permits the circuit to remain stationary while the armature rotates
  without breaking the electrical contact.
• Allows electrons to flow without interruption

Question 9

American and Canadian generators operate at ____ Hz.

Answer 9

60

Question 10

Sine wave

Answer 10

One complete turn
of the generator
armature represents
one cycle.

Question 11

A direct-current generator is made by exchanging the
slip rings for a _________ ,

Answer 11

commutator ring

Question 12

Motors

Answer 12

Convert electrical to mechanical energy

Question 13

voltage and number of turns are _____ proportional,

Answer 13

directly

Question 14

voltage and amperage are ______ proportional.

Answer 14

inversely

Question 15

the number of turns and amperage are _____ proportional.

Answer 15

inversely

Question 16

step-up transformer _______ voltage from primary to secondary while _______ amperage

Answer 16

Increase
Decreasing

Question 17

a step-down transformer _______ voltage from primary to secondary while _______ amperage

Answer 17

Decrease
Increasing

Question 18

rectification

Answer 18

The process by which alternating current is changed to pulsating direct current

Question 19

Ferromagnetic
(Magnetic Classification
of Materials)

Answer 19

-Iron, cobalt and nickel
-Highly permeable and greatly susceptible

Question 20

Paramagnetic (Magnetic Classification
of Materials)

Answer 20

• Platinum and aluminum
• Low permeability and weak attraction

Question 21

Diamagnetic (Magnetic Classification
of Materials)

Answer 21

Beryllium, bismuth, and lead
* Weakly repelled by all magnetic fields

Question 22

Nonmagnetic (Magnetic Classification
of Materials)

Answer 22

Wood, glass, rubber and plastic
* Not affected by magnetic fields

Question 23

Permeability

Answer 23

The ability of a material to become
magnetized

Question 24

Dc motor uses

Answer 24

Commutator rings

Question 25

the unit of resistance

Answer 25

Ohms

Question 26

Resistance Dependent upon four things:

Answer 26

• Material’s conductivity
• Length
• Diameter
• Temperature