Module 3 quiz contains 52 question based on the syllabus for module 3 examination for B1.1, B1.3 and B2 category.

The time limit for the quiz is 65 min.

The number of attempts allowed are unlimited.

All the best.

Name

1.

In the diagram an unknown resistance is being measured using a Wheatstone bridge. The bridge is balanced. The unknown resistance is:

60 Ω

150 Ω

10 Ω

2.

An alternating current generator is operating at 50kVA in a circuit with a power factor of 0.8. The real power is

50kW

72kW

40kW

3.

Three branches in a circuit have currents entering of 3A, 4A and 5A. A fourth branch has 10A leaving. A fifth branch must have:

2A entering

22A leaving

2A leaving

4.

The average Value of an "alternating current" voltage is calculated as:

0.707 x peak value and is measured over half a cycle

0.637 x peak value and is measured over half a cycle

0.637 X peak value and is measured over the whole cycle

5.

An inductor of 50mH is connected in series with a resistance of 10kΩ. The time taken for the current to reach 63.2% of the maximum is:

5 μS

500 μS

50 μS

6.

In an RLC circuit, the power factor is always

Negative

Depends on the circuit

Zero

Positive

7.

Diamagnetic materials have a permeability of:

much greater than 1

slightly greater than 1

slightly less than 1

8.

The aircraft power supply frequency is 400 hertz. The period is:

0.006 seconds

0.0025 seconds

0.004 seconds

9.

The maximum variation between the maximum positive and the maximum negative value is known as?

Peak to peak value

Peak value

Average value

rms value

10.

A synchronous ac motor is most useful for applications requiring:

varying loads such as fuel booster pumps

constant speed such as ventilation fans

intermittent loads such as control surface or door operations

11.

When making up electrolyte for lead acid batteries:

it is safest to add acid to water

equal quantities of water and acid should be used

it is safest to add water to acid

12.

A 24V source is connected across a 30 Kohm resistor. In order to achieve a current flow of 6mA the resistor must be changed to

4 Kohm

7.5 Kohm

144 mohm

13.

An alternating current circuit contains resistance and no reactance the phase angle between voltage and current will be:

45

zero

90

14.

Two 10V 20AH batteries are connected in parallel and connected across a 10Ω load. How long could they supply the required load current before the voltage began to decay?

4 hours

40 hours

10 hours

15.

The retentivity of a material is given by

Remanence / Coercive Force

Coercive Force x Remanence

Coercive Force / Remanence

16.

5 amps passes through a 4 ohm resistor, the amount of power the resistor has to dissipate is:

6.25 watts

100 watts

20 watts

17.

The power factor of an alternating current circuit is:

the cosine of the phase angle

the tangent of the phase angle

the sine of the phase angle

18.

Unit of capacitance is

Henry

Farad

Volts

19.

Calculate the time constant of a series RC circuit consisting of a 100microF capacitor in series with a 100ohm resistor.

0.1 sec

0.01 msec

0.01 sec

0.1 msec

20.

In a lead acid cell, there are:

an equal number of plates

more negative than positive plates

more positive than negative plates

21.

A coil induces 200 mV when the current changes at the rate of 1 amp per second. The inductance L is:

400 mH

100 mH

200 mH

22.

Calculate the current across the 20 ohm resistor

60A

20A

10A

23.

A transformer has 100V applied to the primary. If the ratio is 1:3 and the secondary current is 6A, the primary current will be:

2A

6A

18A

24.

A generator produces Voltage by:

chemical reaction

electromagnetic induction

friction

25.

What is relative permittivity?

Equal to the absolute permittivity

Ratio of absolute permittivity to actual permittivity

Ratio of actual permittivity to absolute permittivity

Equal to the actual permittivity

26.

The charge of 25 x 10^18 electrons is Approximately:

3 coulombs

2 coulombs

4 coulombs

27.

An alternating current series circuit contains resistance of 100 ohms, XL reactance of 100 ohms and XC reactance of 100 ohms. The impedance will be:

100 ohms

33.33 ohms

300 ohms

28.

The unit of Siemens with the symbol G is:

Conductance

Resistance

Reactance

29.

Two resistors in parallel. If they are of unequal value it is true that:

The both ohmic values takes the same current

The highest ohmic value takes the largest current

The lowest ohmic value takes the largest current

30.

An AC motor which rotates at the same speed as supply frequency is called:

a universal machine

a synchronous motor

an induction motor

31.

A coil has an inductance of 8 mH with 125 turns. When the number of turns is doubled within the same length, the inductance will become:

32 mH

4 mH

16 mH

32.

If the resistance of a conductor is 10Ω then it’s conductance is?

0.01 Siemens

0.25 Siemens

0.1 Siemens

33.

When the supply frequency increases, what happens to the capacitive reactance in the circuit?

Decreases

Increases

Becomes zero

Remains the same

34.

The torque speed characteristic of a series motor is:

low torque, low speed

high torque, low speed

high torque, high speed

35.

Battery cells are connected in parallel to:

increase the current capacity

increase the voltage output

increase the internal resistance

36.

An AC generator connected in star with a phase voltage of 115v will have a line voltage of:

199 approximately

205 approximately

195 approximately

37.

What is the maximum number of Electrons in the N shell of an Atom?

18

8

32

38.

For very low frequencies, capacitor acts as

Short circuit

Open circuit

Amplifier

39.

N capacitors having capacitance C are connected in series, calculate the equivalent capacitance.

CN

C

N/C

C/N

40.

The Electron Valence of an Element with 5 electrons is:

5

1

3

41.

Air has a dielectric constant of

Infinity

Unity

Zero

42.

An eight pole generator rotates at 6,000 RPM. The frequency produced is:

400 Hz

800 Hz

1200 Hz

43.

In the Diagram the two unknown resistors are of equal value and their value is:

12 ohm

6 ohm

24 ohm

44.

The statement that "the sum of all voltages around any closed path must equal the applied voltage" is attributed to:

Faraday

Kirchhoff

Lenz

45.

A battery of 18V with an internal resistance of 1.5Ω is connected in a circuit with three resistors in parallel of values 6Ω, 12Ω and 12Ω. The total circuit resistance is:

31.5Ω

4.5Ω

12Ω

46.

An alternating current voltage waveform has a root mean square value of 70.7 volts the peak voltage is:

100 volts

56 Volts

200 volts

47.

20 volts is applied across two resistors in series one 10 Kohm the other 30 Kohm. The current taken from the battery will be:

0.5mA

5mA

0.5A

48.

In a magnetic circuit:

more length of coil produces less field intensity for a specified mmf

air has a higher reluctance than soft iron

more reluctance means more flux for a specified mmf

49.

What is the effective value of current?

Average current

Instantaneous current

RMS current

50.

Resistance is:

Inversely proportional to the product of length and resistivity

Proportional to the cross sectional area

Inversely proportional to the cross sectional area

51.

The voltage waveform in an ideal inductance would be:

90° lagging the current

In phase with the current

90° leading the current

52.

In a parallel network of resistors which are unequal the current is: