2365 - 602 Principles of electrical science

Welcome to your 2365 602 Electrical Science

What is pd?

Positive difference

Potential difference

Potential divider

Positive divider

None

What is the SI unit of measurement symbol for Current?

None

Work done is calculated by multiplying?

Distance x time

Distance per second x mass

Force x velocity

Force x distance

None

A 12V battery is connected across a set of resistors in series, values being, 60Ω, 30Ω, 100 Ω and 45Ω. The current flowing in the circuit is?

0.51mA

5.1A

51A

51mA

None

A d.c. motor takes 9.6 A from a 400 volt supply. Calculate the power input to the motor?

12KW

3.84KW

41.67KW

0.024KW

None

Which of the following electronic components allows to flow in one direction only?

Diac

Diode

Triac

Resistor

None

An immersion heater uses the heating method of?

Radiation

Convection

Immersion

Conduction

None

If two equal wattage lamps were connected in series the volt drop across each of them would?

be the same

equal the supply voltage

be greater across the first lamp

equal the current flowing

None

Which ONE of the following statements is true?

EMF, pd and voltage are measured using different unit

Current cannot flow without pd

Current actually flows from positive to negative

Voltage cannot be present without current

None

10.

If a single loop of wire connected to a commutator is rotated in a permanent magnetic field, the voltage measured at the commutator will be?

A.C

D.C

intermittent

unilateral

None

11.

What is the SI unit of measurement for Time?

Candela

Kelvin

Second

Joule

None

12.

The chemical effect of a current is used in?

Electroplating

Electric welding

Inductive heating

Operation of a capacitor

None

13.

What value of resistance is required to have a current of 12A, from a supply of 230v?

1320A

19.17A

19.17Ω

1320Ω

None

14.

Which best describes the lever in the diagram?

qualifications needed to be an electrician

Class 0

Class 1

Class 2

Class 3

None

15.

Which of the following devices are used to provide temperature control when heating spaces

Room thermometer

rheostat

Room thermostat

simmerstat

None

16.

Which best describes the lever in the diagram?

Class 0

Class 1

Class 2

Class 3

None

17.

Large quantities of electric power are produced in generators or alternators by?

thermal means

magnetic means

chemical means

mechanical means

None

18.

Which in the diagram shows the correct rotation of the magnetic field?

qualifications required to be an electrician

None

19.

Refer to the figure shown. What does value 'A' indicate?

Average value of the waveform

Periodic time of the waveform

RMS value of the waveform

Peak amplitude of the waveform

None

20.

If a motor’s input is 75 Watts and it’s output is 50 Watts, what is the efficiency of the motor?

33.30%

50%

150%

66.60%

None

21.

What is the value of the total resistance in the diagram?

89Ω

9.25Ω

89A

9.25A

None

22.

What is the formula for average mechanical power?

P = W/t

P=D/W

P = t/W

P = I X R

None

23.

A length of a conductor has a resistance of 1Ω . If its cross sectional area was doubled its resistance would be?

0.25Ω

0.5Ω

2Ω

4Ω

None

24.

What is the SI unit of measurement symbol for Mass?

None

25.

How long will a single rotation of a generator take with the frequency of 50Hz?

2ms

20ms

50ms

100ms

None

26.

Which two values of a right-angled triangle are used to calculate the tangent of an angle?

Opp and Hyp

Adj and Hyp

Right angle and Opp

Adj and Opp

None

27.

What is the SI unit of measurement for Current?

Watt

Ampere

Ohm

Volt

None

28.

The resistivity of an electrical conductor depends on its?

length/cross-sectional area

material

length

cross-sectional area

None

29.

In the triangle shown what is the length of side 'A'?

80m

10m

28.28m

57.01m

None

30.

What is the formula for electrical charge?

Q = I x R

Q = P x I

Q = I x t

Q = V x I

None

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2365 – 602 Principles of electrical science