Basic Electricity

Question 1

Name two examples of insulators

Answer 1

Mica, glass, wood, rubber

Question 2

Name two examples of good conductors

Answer 2

copper, silver, gold

Question 3

Name an example of a semi-conductor

Answer 3

silicon, germamnium

Question 4

A good conductor has 1-__ valence electrons

Answer 4

1-2

Question 5

A good insulator has __ valence electrons

Answer 5

8

Question 6

A semi-conductor has __ valence electrons

Answer 6

4

Question 7

one coulomb is 6.25x10 to the power of 18 electrons

Answer 7

yes

Question 8

Ampere is described as one _______ per second

Answer 8

coulomb

Question 9

poles are where the magnetic lines of force enter and leave the _______

Answer 9

magnet

Question 10

The North Pole always points to the ______ pole of the magnetic

Answer 10

south

Question 11

magnetic lines of force always complete ______

Answer 11

loops

Question 12

A ferromagnetic material is any material that behaves like _____ in a magnetic field

Answer 12

iron

Question 13

Flux density - stronger magnetic force means more lines of _____ per area

Answer 13

force

Question 14

Magnetic screen is where magnetic lines of force pass through _______

Answer 14

anything

Question 15

Residual magnetism Is the ability of a material to hold a magnetic _____

Answer 15

field

Question 16

Factors that affect strength of an electromagnet

1. number of ____
   2, spacing between ____
2. type of ______ used
3. amount of _____ flow

Answer 16

1. number of turns
2. spacing between turns
3. type of material used
4. amount of current flow

Question 17

A screen uses soft iron to shield a device, providing an alternate path for the magnetic ____

Answer 17

field

Question 18

Reluctance is the property that opposes the setting up of ____ lines

Answer 18

flux

Question 19

Name three methods of demagnetizing?

Answer 19

electrical current

heat

vibration

Question 20

three precautions to avoid damaging magnets

Answer 20

1. do not heat
2. do not expose to AC
3. do not expose to vibration
4. don’t store magnet near another magnet

Question 21

What is a keeper?

Answer 21

A soft iron piece placed across poles to provide easy path for flux

Question 22

Low voltage?

Answer 22

31v-750v

Question 23

High voltage?

Answer 23

751v or more

Question 24

Extra low voltage?

Answer 24

30v or less

Question 25

Name two advantages of AC?

Answer 25

1. AC can be stepped up or down | 2. alternators can be manufactured with much higher voltage and power ratings

Question 26

What is an alternation?

Answer 26

one full wave form

Question 27

Frequency is the number of times per second a _______ repeats itself

Answer 27

waveform

Question 28

Peak value is the maximum value or current or voltage in an AC ______

Answer 28

waveform

Question 29

Average value is the average value based on ___________ values

Answer 29

instantaneous

Question 30

"RMS" means

Answer 30

root means square

Question 31

"In phase" is when the voltage wave and current wave reach peak values, and 0 values at ______ point in time

Answer 31

same

Question 32

"Out of Phase" is when voltage and current wave reach peak values, and 0 values at ______ points in time

Answer 32

different

Question 33

Phase angle is the difference in _______ between one phase, or value and another

Answer 33

degrees

Question 34

Name four factors affecting inductance

Answer 34

1. number of turns 2. coil diameter 3. length of the coil 4. core material

Question 35

A Henry describes the amount of resistance in an _______ load

Answer 35

inductive

Question 36

Farad is the basic unit of ________ where one coulomb of charge for 1 second yields a potential difference of 1 volt

Answer 36

capacitance

Question 37

capacitors can _____ voltage to increase motor efficiency

Answer 37

slow

Question 38

"ICE' means current in a capacitive circuit slows ______

Answer 38

voltage

Question 39

In a resistive circuit voltage and current are in _____

Answer 39

phase

Question 40

In an inductive circuit the current lags voltage by ____ degrees

Answer 40

90

Question 41

In a capacity circuit the current leads voltage by ___ degrees

Answer 41

90

Question 42

Name three reasons for power loss in transformers

Answer 42

1. resistance in the windings 2. hysteresis 3. eddy currents

Question 43

electrical equipment voltage imbalance must be within __%

Answer 43

2%

Question 44

electrical equipment current imbalance must be within __%

Answer 44

10%