Electrical Engineering Quiz 5

1 / 50

The attraction capacity of electromagnet will increase if the_______________?

core length increases i

core area increases

flux density increases

flux density decreases

2 / 50

Parson?s turbine is___________?

simple single wheel, impulse steam turbine

pressure compounded steam turbine

multi wheel reaction steam turbine

simple single wheel reaction steam turbine

3 / 50

The curve between V and I of SCR when anode is positive w.r.t cathode and when anode is negative w.r.t cathode are known as_____________________?

both as forward characteristics

former as reverse characteristics and later as forward characteristics

former as forward characteristics and later as reverse characteristics

both as reverse characteristics

4 / 50

During load shedding:

system voltage is reduced

system power factor is changed

some loads are switched off

system frequency is reduced Efficiency is the secondary consideration in

5 / 50

Volt box is a component to_____________?

extend voltage range

measure voltage

compare voltage in a box

none of the above

6 / 50

When a conductor carries more current on the surface as compared to core, it is due to___________?

skin effect

unsymmetrical fault

corona

permeability variation

7 / 50

IC = aIE +____________?

ICBO

ICEO

?IB

8 / 50

What is used to protect a thyristor from high di / dt conditions__________?

Inductor

Snubber circuit

Fuse.

Voltage clamping device

9 / 50

Which of the following motor has the poorest speed regulation ?

Shunt motor

Cumulative compound motor

Series motor

Differential compound motor

10 / 50

Long distance railways use which of the following ?

25 kV single phase A.C.

200 V D.C.

25 kV two phase A.C.

25 kV three phase A.C.

11 / 50

For Parson?s reaction steam turbine, degree of reaction is____________?

100%

50%

60%

75%

12 / 50

1 volt/meter is same as___________?

1 meter/coulomb

1 joule/coulomb

1 newton/meter

1 newton meter

13 / 50

If the anode current is 800 A, then the amount of current required to turn off the GTO is about____________?

200 A

400 A

20 A

600 A

14 / 50

The effects of EMI can be reduced by_____________?

Reducing the susceptibility of the receptor

All of these

Suppressing emissions

Reducing the efficiency of the coupling path

15 / 50

The leakage current across a pn junction is due to________________?

Minority carriers

Junction capacitance

None of the above

Majority carriers

16 / 50

If the load resistance decreases in a Zener regulator, then Zener current ______________?

Decreases

Stays the same

Increases

None of the above

17 / 50

What will be the collector efficiency of a power amplifier having zero signal power dissipation of 5 watts and a.c. power output of 2 watts ?

40%

80%

50%

20%

18 / 50

Relative permeability of vacuum is__________?

1 H/m

1/4JI

4n x 10-? H/m

19 / 50

capacitors are used for audio frequency and radio frequency coupling and tuning ?

Mica

Air

Ceramic

Plastic film

20 / 50

Total number of crystal systems is____________?

21 / 50

What will be the magnetic potential difference across the air gap of 2 cm length in magnetic field of 200 AT/m ?

2 AT

10 AT

4 AT

6 AT

22 / 50

Six resistors are in parallel. The two lowest-value resistors are both 1.2 k?. The total resistance______________?

is less than 6 k?

is less than 600 ?

is greater than 1.2 k?

is less than 1.2 k?

23 / 50

In split-phase motor auxiliary winding is of___________?

thin wire placed at the top of the slots

thick wire placed at the top of the slots

thin wire placed at the bottom of the slots

thick wire placed at the bottom of the slots

24 / 50

Materials subjected to rapid reversal of magnetism should have______________?

high co-ercivity and low density

large area oiB-H loop

high co-ercivity and high retentivity

high permeability and low hysteresis loss

25 / 50

Insertion of reactance in the rotor circuit_______?

increases starting torque but maxi-mum torque remains unchanged

reduces starting torque as well as maximum torque

increases starting torque but maxi-mum torque decreases

increases starting torque as well as maximum torque

26 / 50

During discharge, the active material of both the positive and negative plates is changed to___________?

PbS04

Pb02

PbO

27 / 50

Which of the following alternatives will be cheaper ?

Five motors of 20 H.P. each

Ten motors of 10 H.P. each

Four motors of 25 H.P. each

A 100 H.P. A three phase motor

28 / 50

The power scale of circle diagram of an induction motor can be found from__________?

stator resistance test

short-circuit test only

noue of the above

no-load test only

29 / 50

The Q of the crystal is of the order of____________?

100

1000

More than 10,000

30 / 50

The maximum efficiency of resistance loaded class A power amplifier is _________________?

25%

50%

30%

31 / 50

Damping of the Ballistic galvanometer is made small to_______________?

get first deflection large

get minimum overshoot

make the system critically damped

make the system oscillatory

32 / 50

All of the following are equivalent to watt except_____________?

amperes x volts

joules/seC.

amperes/volt

(amperes) ohm

33 / 50

The best indication about the state of charge on a lead-acid battery is given by____________?

specific gravity of electrolyte

none of the above

output voltage

temperature of electrolyte

34 / 50

Short-circuit test on an induction motor cannot be used to determine___________?

power scale of circle diagram

windage losses

transformation ratio

copper losses

35 / 50

Copper brushes in D.C. machine are used_____________?

where low voltage and high currents are involved

in both of the above cases

in none of the above cases

where high voltage and small cur-rents are involved

36 / 50

In a shaded pole single-phase motor, the revolving field is produced by the use of_________?

resistor

shading coils

inductor

capacitor

37 / 50

To send 10% of the main current through a moving coil galvanometer of resistance 99 O the shunt required is______________?

11 O

100 O

9 O

38 / 50

Mercury is a choice with steam in binary vapour cycle because it has____________?

relatively low vapourisation pressure

all above

higher critical temperature and pressure

higher saturation temperature than other fluids

39 / 50

An average voltage of 10 V is induced in a 250 turns solenoid as a result of a change in flux which occurs in 0.5 second. The total flux change is____________?

2 Wb

0.02 Wb

20 Wb

0.2 Wb

40 / 50

In a rotary converter I2R losses as compared to a D.C. generator of the same size will be___________?

less

same

three times

double

41 / 50

A thyristor string is made of a no. of SCR connected in series and parallel. The string have volume and current of 11 KV and 4 K The voltage and current rating of available SCRs are 1800 V and 1000 For a string efficiency of 90 % let the number of SCRs in series and parallel are a and b respectively. Then the value of a and b will be_____________?

7, 5

5, 7

4, 6

6, 4

42 / 50

In conductors conduction of electricity takes place due to movement of_______________?

positive and negative ions

positive ions only

negative ions only

electrons only

43 / 50

In resistance heating highest working temperature is obtained from heating elements made of_____________?

silicon carbide

nickel copper

nichrome

silver

44 / 50

PVC stands for____________?

pressed and varnished cloth

polyvinyl chloride

positive voltage conductor

post varnish conductor

45 / 50

The following constitute short-circuit in the armature winding.

Two of more turns of the same coil getting grounded

Insulation failure between two commutator bars

All of the above

Insulation failure between two turns of a coil

46 / 50

If a 6 uF capacitor is charged to 200 V, the charge in coulombs will be____________?

900 uC

800 uC

1200 uC

1600 uC

47 / 50

In a series resonant band-pass filter, a lower value of Q results in______________?

a higher resonant frequency

a smaller bandwidth

a larger bandwidth

a higher impedance

48 / 50

When an ammeter is inserted in the circuit, the circuit current will _____________?

Decrease

None of the above

Remain the same

Increase

49 / 50

In a series parallel circuit, any two resistances in the same current path must be in___________?

series with each other

series with the voltage source

parallel with each other

parallel with the voltage source

50 / 50

In parallel resonance, the circuit impedance is_________________?

L/CR

R/LC

C/LR

CR/L

Provide Your Information

NameEmailPhone Number

Your score is

The average score is 95%