Free Printable Electrical principles

1.

What is ⅜ converted to a decimal?

a)

0.375

b)

2.67

c)

0.725

d)

0.4

2.

13m of a 50m drum of cable is used. What is the percentage left on the drum?

a)

26%

b)

50%

c)

74%

d)

13%

3.

$R\ =\ \frac{pL}{A}$

Make resistivity the subject of the formula, .

a)

$p\ =\ \frac{RA}{L}$

b)

$R\ =\ \frac{AL}{p}$

c)

$R\ =\ \frac{pL}{A}$

d)

$p\ =\ \frac{L}{RA}$

4.

$a^2\ =\ b^2\ =\ c^2$

Rearrange the following formula to make ‘c’ the subject:

a)

$c\ =\ \sqrt{a^2\ -\ b^2}$

b)

$c\ =\ \sqrt{b^2\ -\ a^2}$

c)

$c\ =\ \sqrt{a^2\ +\ b^2}$

d)

$c\ =\ \sqrt{b^2\ +\ a^2}$

5.

How can 25kV be expressed in a different way?

a)

$25\ x\ 10^6$

b)

$25\ x\ 10^3$

c)

$25\ x\ 10^{-3}$

d)

$25\ x\ 10^{-6}$

6.

How can 23mA can also be shown?

a)

$23\ x\ 10^3$

b)

$23\ x\ 10^6$

c)

$23\ x\ 10^{-3}$

d)

$23\ x\ 10^{-6}$

7.

Four different meters are used to measure the resistance of a CPC.

What is the average reading if, individually they were: 1.3Ω, 1.05Ω,

1.24Ω, 1.12Ω?

a)

1.18

b)

1.2

c)

4.71

d)

1.51

8.

An ohmmeter takes five readings on a circuit: 0.24Ω, 0.79Ω, 0.26Ω,

0.35Ω, 0.56Ω. What is the ‘range’ of the readings?

a)

0.55

b)

0.79

c)

0.24

d)

2.16

9.

The SI unit m2 is used for what measurement?

a)

Volume

b)

Length

c)

Area

d)

Mass

10.

What are the SI base units for volume and temperature?

a)

m3, °C

b)

m2, °K

c)

m2, °C

d)

m2, °K

11.

What is the volume of a room that measures, 6m long by 3.9m wide and is 250cm high

a)

12.4m3

b)

23.4m2

c)

23.4m3

d)

58.5m3

12.

An industrial motor has a mass of 500kg at sea level. What is the

motor’s mass when it is taken 1,000m above sea level?

a)

5,000kg

b)

4.9kN

c)

5,000N

d)

500kg

13.

What is the correct formula to determine mass?

a)

Force x distance

b)

Force x gravity Force x gravity

c)

Density x volume

d)

Density/volume

14.

Convert 2½ minutes into the correct base unit.

a)

2 minutes, 30 seconds

b)

1/24th of an hour

c)

150s

d)

170s

15.

What is 0°K approximately in centigrade?

a)

-273°C

b)

273°C

c)

-459°C

d)

0°C

16.

What is the SI unit for frequency?

a)

Hz

b)

S

c)

mS

d)

J

17.

What is the SI unit for power?

a)

MW

b)

mW

c)

W

d)

kW

18.

What is inductive reactance measured in?

a)

Henrys

b)

Farads

c)

Ohms

d)

Watts

19.

What is the symbol for current?

a)

I

b)

A

c)

mA

d)

Ω

20.

What does EMF stand for?

a)

Electro-magneto force

b)

Electro-motive force

c)

Electron motive force

d)

Electron magneto force

21.

What does the sub-multiple, ‘pico’ mean?

a)

x 10-6

b)

x 10-12

c)

x 10-9

d)

x 10-15

22.

What is reactive power also known by?

a)

KVAr

b)

W

c)

KVA

d)

KW

23.

What is the correct formula for resistance?

a)

$R\ =\ \frac{p}{I^2}$

b)

$R\ =\ VI$

c)

$R\ =\ \frac{I}{V}$

d)

$R\ =\ \frac{P}{I}$

24.

What are the correct units for capacitance and inductance?

a)

Farads and ohms

b)

Farads and henrys

c)

Reactance and ohms

d)

Reactance and resistance

25.

What is true power?

a)

kVA

b)

VA

c)

kW

d)

kVAr

26.

What range would an ohmmeter be set to for the most accurate

reading of a 1.99Ω cable?

a)

0–100Ω

b)

0–1kΩ

c)

0–10kΩ

d)

0–10kΩ

27.

If 400V is supplied to a circuit that draws 14A, what is the power

being consumed by the circuit?

a)

5.6kW

b)

28.57W

c)

0.035W

d)

56kW

28.

What is the best instrument to measure frequency?

a)

Low-reading ohmmeter

b)

High-reading ohmmeter

c)

Voltmeter

d)

Oscilloscope

29.

What is impedance measured in?

a)

Ohms

b)

Volts

c)

Amperes

d)

Watts

30.

Impedance is made up of what components?

a)

Resistance and power

b)

Resistance and reactance

c)

Reactance and reluctance

d)

Current and resistance

31.

How much does a 5kg cable drum weigh?

a)

5kg

b)

5N

c)

49.05N

d)

10N

32.

What is the value of gravity at sea level?

a)

9.81mS-2

b)

90.8mS-2

c)

10mS-1

d)

981mS2

33.

A 1,000kg transformer exerts a force of approximately what on the ground?

a)

9.81kN

b)

100N

c)

981N

d)

98kN

34.

Joules and watts are measurements of what?

a)

Energy and voltage

b)

Energy and current

c)

Power and inductance

d)

Energy and power

35.

A cable drum has a mass of 10kg and is lifted 2.5m to a shelf. How

much energy is used?

a)

25J

b)

25N

c)

245.25W

d)

245.25J

36.

What is the energy stored in a drill called when it is sitting on

the floor?

a)

Centripetal

b)

Centrifugal

c)

Kinetic

d)

Potential

37.

A drill falling off a ladder has what type of energy?

a)

Centripetal

b)

Centrifugal

c)

Kinetic

d)

Potential

38.

How much power is used when 200J of energy is expended in moving a

load in 3.4 seconds?

a)

58.82W

b)

680W

c)

577W

d)

200W

39.

A 45kg motor is lifted 3m in to a shelf in 5 seconds. How much

power is used?

a)

675W

b)

264.87W

c)

6.62kW

d)

660W

40.

A crane uses 3.4kW of power to lift a 200kg mass in 6.7s. How far has

the load moved?

a)

111.7m

b)

1117.36m

c)

11.61m

d)

4.556km

41.

A 109kg mass is moved to a height of 10m in 16s. How much power is

used?

a)

668.3W

b)

10.69kW

c)

17.44kW

d)

290W

42.

How long does it take to move a load if 1,000W of power is used and 2,000J of energy is expended

a)

0.5s

b)

55 hours

c)

2s

d)

5.5 hours

43.

Current is the flow of what?

a)

Electrons

b)

Protons

c)

Neutrons

d)

Atoms

44.

In which state are atoms least densely packed?

a)

Water at -273°C

b)

Steam

c)

Water

d)

Ice

45.

What is an insulator?

a)

A material with lots of electrons in

the outer shell

b)

A material with freely moving

electrons

c)

A material with few electrons in the

outer shell

d)

A material with freely moving protons

46.

What is a conductor?

a)

A material with freely moving

electrons

b)

A material with lots of electrons in

the outer shell

c)

A material with tightly bound

electrons in the outer shell

d)

A material with freely moving protons

47.

What happens if you heat an aluminium conductor?

a)

The resistance increases

b)

The resistance decreases

c)

The impedance decreases

d)

The reactance improves

48.

What application is mineral insulated cable particularly suitable for?

a)

Fire alarm cable

b)

Connections to motors

c)

Domestic sockets

d)

Domestic lighting

49.

What application is thermosetting steel wire armoured cable particularly suited to?

a)

Domestic lighting

b)

Boiler connection

c)

Domestic sockets

d)

Feeding an outbuilding

50.

What is the resistance of 120m of copper 4mm2 cable if

it has a resistivity of 0.0178μΩ/m?

a)

1.5Ω

b)

6.8Ω

c)

0.534Ω

d)

8.54Ω

51.

Steel conduit with a resistivity of 0.12μΩ/m and an overall CSA of 34mm² is to be used as a circuit CPC. What is the resistance if the conduit run is 20m

a)

0.071Ω

b)

7Ω

c)

0.5Ω

d)

1Ω

52.

If resistors are added up to find the total circuit resistance, what type of circuit is it

a)

Combined series and parallel

b)

Shunt

c)

Series

d)

Parallel

53.

If resistors are added up using reciprocals to find the total

circuit resistance, what type of circuit is it?

a)

Parallel

b)

Series

c)

Combined series and parallel

d)

Reactive

54.

What is the resistance of a circuit if the current drawn from a

400V supply is 17.3A?

a)

23.12Ω

b)

0.043Ω

c)

2.3Ω

d)

4.3Ω

55.

What current is drawn from a 200V supply if a 4Ω load is connected?

a)

0.02A

b)

20A

c)

5A

d)

50A

56.

Which of the following is NOT an Ohm's law equation?

a)

V = RI

b)

V = IR

c)

I = V/R

d)

R = VI

57.

If four equal resistors are connected in series and then across a

230V supply what will be the voltage across a single resistor?

a)

920V

b)

9.2V

c)

57.5V

d)

230V

58.

If 5 x 2Ω resistors are connected in series and then to a 115V supply, what will be the current drawn by the circuit

a)

57.5A

b)

230A

c)

2.3A

d)

11.5A

59.

If six resistors are connected in parallel and they are all 12Ω,

what is the total circuit resistance?

a)

24Ω

b)

6Ω

c)

2Ω

d)

12Ω

60.

If a 6Ω resistor is connected in series with a 13Ω resistor and

then connected across a 220V supply, what is the total circuit power

consumption?

a)

2.86 kW

b)

2.55kW

c)

4.18kW

d)

15kW

61.

4 x 5Ω resistors are connected in series. What is the voltage drop

across the first resistor if the supply is 115V?

a)

28.75V

b)

23V

c)

0V

d)

115V

62.

If four resistors of 29Ω each are connected in parallel, what is

the total power of the circuit if the supply is 200V?

a)

6.9W

b)

23.2kW

c)

200W

d)

5.52kW

63.

A line conductor measures 0.66Ω and the neutral measures 0.67Ω.

What is the voltage drop of the circuit if connected to a domestic supply

with a design current of 5A?

a)

3.96A

b)

4.02V

c)

6.65A

d)

6.65V

64.

The line and neutral conductors measure 0.44Ω each and the CPC

measures 0.56Ω. If they are connected to a load that is designed to take

10A, what will the volt drop be on the circuit?

a)

8.8V

b)

12V

c)

10V

d)

5.6V

65.

If two dissimilar metals are connected by a cell at one end, and

the other ends placed in a conductive solution, what will happen?

a)

Condensation

b)

Electrolysis

c)

Osmosis

d)

Insulation

Electrical principles

Total questions: 65

Worksheet time: 5hrs 25mins

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