General: Basic Electricity 🔊

Question 1

What is the most important law applicable to the study of electricity?

Answer 1

Ohm’s Law

Question 2

What are the elements of ohm’s law?

Answer 2

Voltage (E), current (l), and resistance (R)

Question 3

What are four sources of electrical energy?

Answer 3

Thermal, light, pressure, and chemical

Question 4

What does an electrical circuit consist of?

Answer 4

1. A source (battery)
2. Resistance or load (light bulbs)
3. Conductors (wires)

Question 5

What represents capacitance in an AC circuit?

Answer 5

A capacitor (same as a condenser)

Question 6

What is the function of a capacitor?

Answer 6

To store electricity

Question 7

What is the unit of measure for capacitance?

Answer 7

Farad

Question 8

What is the standard unit of measure for frequency?

Answer 8

Hertz

Question 9

What is the basic component that only allows current to flow in one direction?

Answer 9

A Diode (acts like a check valve)

Question 10

What is inductance?

Answer 10

When voltage is induced by magnetic flux lines in a coil in an AC circuit. The induced voltage is opposite and direction to the applied voltage and opposes any change in the alternating current.

Question 11

What is an example of an inductor in a magneto?

Answer 11

The coil

Question 12

What is impedance?

Answer 12

The total opposition for AC to flow caused by the combined effect of resistance, inductive reactance, and capacitive reactance in an AC circuit.

Question 13

What causes opposition to the flow of current in an AC circuit?

Answer 13

Inductive and capacitance reactance

Question 14

What is the unit of measurement for impedance?

Answer 14

Ohms

Question 15

What is the general purpose of a resistor?

Answer 15

To limit current

Question 16

How may the value of a small, fixed resistor be determined?

Answer 16

By the colored bands on the resistor

Question 17

What are two things that happen when current flows through a conductor?

Answer 17

A magnetic field is generated and the conductor heats up

Question 18

What is the common name for the lines of force that make up a field surrounding a magnet?

Answer 18

Magnetic flux lines

Question 19

What is the concept that describes the relationship between electricity and magnetism?

Answer 19

Electromagnetism

Question 20

What are the four factors that affect the resistance of an electrical conductor?

Answer 20

The wire gauge, length, temperature, and material

Question 21

What is the unit of measurement of power in a DC circuit?

Answer 21

Watts. Ampers x volts = watts. 746 watts = 1 horsepower.

Question 22

What is a kilowatt?

Answer 22

1000 watts

Question 23

In a DC circuit, what occurs when voltage is increased while resistance remains constant?

Answer 23

There will be an increase in current

Question 24

What are the three types of DC electrical circuits?

Answer 24

Series circuits, parallel circuits, and complex circuits which are series and parallel circuits.

Question 25

How many cells does a 24 volt lead acid battery have?

Answer 25

12 cells, with each rated at approximately 2 volts

Question 26

What are the units that battery capacity is measured in?

Answer 26

Ampere hours

Question 27

What should be the specific gravity in a fully charged lead acid battery?

Answer 27

It should be between 1.275 and 1.3

Question 28

What instrument is used to determine the specific gravity of electrolyte in a lead acid battery?

Answer 28

A hydrometer

Question 29

Why can I hydrometer not be used to determine the charge of a nickel cadmium battery?

Answer 29

The specific gravity of the electrolyte and a nickel cadmium battery does not change appreciably during charge or discharge of the battery.

Question 30

When using a hydrometer to check the charge of a lead acid battery, at what temperature must correction factor be applied to the reading?

Answer 30

Adjustments must be made if temperature of the electrolyte is above 90° f or below 70° f

Question 31

What is electromagnetic induction?

Answer 31

It’s the transfer of electrical energy by means of a magnetic field, transferring voltage from one conductor to another without physically touching. This is the principal of transformer operation.

Question 32

How are battery compartments protected against corrosion?

Answer 32

They are coated with a special corrosion resistant paint such as bituminous paint

Question 33

What should be the correct electrolyte level in a properly serviced battery?

Answer 33

It should be approximately 3/8 in above the plates. If the battery has baffle plates above the cell plates, the electrolyte level should be up to the holes in the baffle plate on each cell.

Question 34

What are paralleling generators and how is the load distributed?

Answer 34

This is when two or more generators are operated at the same time to supply power for a load that must be shared equally

Question 35

Describe no trip or trip free circuit breakers.

Answer 35

A trip free breaker makes it impossible to manually hold the circuit closed when excessive current is flowing. It pops when the circuit gets hot and can’t be reset until it has cooled off.

Question 36

Can you store ni-cad and lead-acid batteries together?

Answer 36

No, the fumes from the lead-acid battery can contaminate the electrolytes in the ni-cad battery.

Question 37

What is the result of an imbalance cell in a nickel-cadmium battery?

Answer 37

When a cell has a low internal resistance, the current will increase across the cell causing it to heat up.

Question 38

What happens to the specific gravity of the electrolyte in a lead acid battery when the temperature changes?

Answer 38

The specific gravity reading on a hydrometer will vary with temperature variations. For example, as the temperature of the electrolyte increases the specific gravity reading will be high. Colder electrolytes will have a lower apparent reading.

Question 39

What is an LED?

Answer 39

Light emitting diode

Question 40

What is an SLA battery?

Answer 40

Sealed lead acid battery

Question 41

What is the basic unit of measurement for inductance?

Answer 41

Henry

Question 42

What prevents reverse current flow in a DC alternator?

Answer 42

Reverse current cutout

Question 43

How many wires may be installed on a single terminal lug?

Answer 43

Four

Question 44

How do you identify wire types?

Answer 44

The lettering on the insulation

Question 45

Name some functions of a multimeter.

Answer 45

They can read volts, current, and resistance

Question 46

Name two types of resistors.

Answer 46

Variable and fixed