3.3 Electrical Terminology

Question 1

What does the SI prefix giga represent ?

Answer 1

10x^9 or 1,000,000,000

Question 2

What does the SI prefix mega represent?

Answer 2

10x^6 or 1,000,000

Question 3

What does the SI prefix kilo represent?

Answer 3

10x^3 or 1,000

Question 4

What does the SI prefix milli represent?

Answer 4

10x^-3 or 0.001

Question 5

What does the SI prefix micro represent?

Answer 5

10^-6 or 0.000 001

Question 6

What does the SI prefix nano represent?

Answer 6

10x^-9 or 0.000 000 001

Question 7

What does the SI prefix pico represent?

Answer 7

10x^-12 or 0.000 000 000 001

Question 8

What is the difference between MW and mW in relation to the SI prefix?

Answer 8

MW is mega watts 10x^6 and mW is milli watts 10x^-3

Question 9

What is voltage?

Answer 9

Is a measure of the difference in electrical charge between two points

Question 10

What is voltage also referred to as in simpler terms?

Answer 10

Electrical pressure

Question 11

What is the SI unit for voltage?

Answer 11

Volts

Question 12

What is the equation for voltage?

Answer 12

V= E/Q
(V=voltage, E=energy transferred in joules, Q= charge in coulombs)

Question 13

What are the two types of electric voltage?

Answer 13

Direct current (DC) voltage and Alternating current (AC) voltage

Question 14

What are all voltages classified as?

Answer 14

Potential difference (PD) or an Electromotve Force (EMF)

Question 15

How do you define DC voltage?

Answer 15

If voltage maintains the same polarity over time even if the value changes

Question 16

How do you define AC voltage?

Answer 16

If a voltage magnitude and polarity change over time

Question 17

What is electromotive force (EMF)?

Answer 17

The voltage of the supply and is a measure of the energy transferred to the circuit

Question 18

What is potential difference?

Answer 18

A measure of the energy transferred from electrical energy to other forms of energy when a current flows (bonding check)

Question 19

How is a voltmeter set up?

Answer 19

In parallel wit the terminals of a power source and/or a load

Question 20

What are the two different ways to indicate the measured voltage?

Answer 20

-pointer deflection (analogue)
-numerical read-out (digital)

Question 21

Why is it said that voltmeters don’t have current flow through them?

Answer 21

They have a very high resistance (considered infinite in calculations)

Question 22

How many volts is a typical aircraft AC power supply?

Answer 22

115v

Question 23

How many volts is a typical aircraft DC power supply?

Answer 23

28v

Question 24

What are the typical volts of a single cell battery?

Answer 24

1.5v

Question 25

What is electric current?

Answer 25

The number of coulombs of charge flowing through the cross section of a conductor in one second

Question 26

What is the unit for current?

Answer 26

Ampere (amps)

Question 27

What symbol is used for current?

Answer 27

I

Question 28

What has an effect on the current being higher or lower?

Answer 28

The Electromotive force (EMF) and the resistance of the circuit

Question 29

What does the speed of movement of electrical charges depend on?

Answer 29

-conductor material -conductor cross-section -potential difference -temperature

Question 30

What is used to measure electric current?

Answer 30

An ammeter (ampere meter) or current meter

Question 31

Electrical resistance is said to be the opposite of?

Answer 31

The opposite to flow of electric current

Question 32

What does electrical resistance measure?

Answer 32

How much energy is required to case a current to flow

Question 33

When resistance is high what happens to the potential difference?

Answer 33

To obtain the same current it must be increased

Question 34

What are the units for resistance?

Answer 34

Ohms Ω

Question 35

What are the units for voltage?

Answer 35

Volts V

Question 36

What are the units for current?

Answer 36

Ampere A

Question 37

Why is temperature given off from a conductor when electricity is passed through?

Answer 37

Because the electrons collide with the ions to cause friction and produce heat

Question 38

When you apply voltage what direction do the electrons travel in?

Answer 38

Negative to positive

Question 39

If there was only electrons in a conductor what would happen if a voltage is supplied?

Answer 39

Their movement would accelerate

Question 40

How does cross sectional area of a conductor affect the resistance of the conductor?

Answer 40

The resistance goes up when the conductor get’s narrower

Question 41

If a something has a high resistance what is the conductance said to be?

Answer 41

Low

Question 42

If something has a low resistance what is the conductance said to be?

Answer 42

High

Question 43

Conductance is reciprocal to?

Answer 43

Resistance

Question 44

What is conductance measured in?

Answer 44

Siemens

Question 45

When you apply voltage to circuit what direction does the current flow?

Answer 45

Positive to negative

Question 46

What is conventional current flow?

Answer 46

The direction in which positive charges move

Question 47

Why is conventional current flow only found in liquids and gases?

Answer 47

Because the positive charges in metals are fixed in place

Question 48

What decides the direction that electrons travel in?

Answer 48

The polarity of the applied voltage

Answer 49

The polarity of the applied voltage

Question 50

What does an electrical supply do?

Answer 50

It separates charges by by forcing electrons from the positive to the negative