Important electrical miscellaneous question

 

ELECTRICAL ENGINERRING MCQ QUESTION

Q1. For a fault in a power system, the term critical clearing time is related to,

(A) Transient stability limit

(B) Reactive power limit

(D) Steady state stability limit

(C) Short circuit current limit

Q2. The rate of rise of re-striking voltage (RRRV) is dependent upon,

(A) Resistance of the system only

(B) Inductance of the system only

(C) capacitance of the system only

(D) Inductance and capacitance of the system

Q3. One of the main advantages of Swinburne's test is that it,

(A) is applicable both to shunt and compound motors

(B) Needs one running test

(C)is very economical and convenient

(D) ignores any change in iron loss

Q4. A 6 pole, 50 Hz, 3-0 induction motor is running at 950 rpm and has rotor Cu loss of 5kW. Its rotor input is kW

(A) 100

(B)110

(C)95

(D) 5.3

Q5. In the shaded pole squirrel cage induction motor the flux in the shaded part always

(A) Leads the flux in the un-shaded pole 

(B) lags the flux in the un-shaded pole segment

(C) is in out of phase with the flux in the 

(D) is in phase with the flux in the

un-shaded pole segment

un-shaded pole segment

Q6. A saturable core reactor is basically a

(A) variable resistor

(B) step down transformer

(C) thermal relay

(D) variable impedance

Q7. If a body reflects entire radiation incident on it then it is known as,

(A) Black body

(B) Grey body

(C) White body

(D) Transparent body

Q8. The ilumination is directly proportional to the cosine of the angle made by the normal to

the illuminated surface with the direction of the incident flux. Above statement is associated with

(A) Planck's law

(B) Macbeth's law of illumination

(C) Bunsen's law of illumination

(D) Lambert's cosine law.

Q9. The concentration of minority carriers in an extrinsic semiconductor under equilibrium is

(A) Directly proportional to thee

doping concentration

(B) Inversely proportional to the doping Concentration

(C) Directly proportional to the

intrinsic concentration

(D) Inversely proportional to the intrinsic concentration

Q10. Reactance relay is normally preferred for protection against

(A) Over load currents only

(B) Phase faults only

(C) Earth faults only

(D) High voltage protection only

Q11. If a combination of HRC fuse and circuit breaker is used, the C.B. operates for

(A) Low overload currents

(B) short circuit current

(C) Under all abnormal current

(D) The combination is never used in practice

Q12. Lightning arrestor should be located

(A) away from the circuit breaker

(B) near the circuit breaker

(C) near the transformer

(D) away from the transformer

Q13. Ferranti effect on long overhead lines is experienced when it is

(A) Lightly loaded

(B) On full load at unity p. f.

(C) On full load at 0.8 p. f. lag

(D) overloaded condition

Q14. In a nuclear power station, moderator is used to,

(A) absorb neutrons

(B) reduce the speed of neutrons

(C) accelerate the speed of neutrons

(D) stop chain reactions

Q15. What is the output waveform when Vin is given square wave?

(A) Square wave

(B) Sine wave

(C) triangle wave

(D) Saw tooth wave

Q16. A pony motor is used for the starting of which of the following motor

(A) Squirrel cage Induction motor

(B) Schrage Motor

(C) Synchronous Motor

(D) Hysteresis Motor

Q16. A PWM switching scheme is used with three phase inverter to

(A) reduce low order harmonics and increase high order harmonics

(B) minimize the load on the DC side.

(C) increase the life of the batteries.

(D) reduce the total harmonic distortion with modest filtering

Q17. The earth wire should not be thinner than a

(A) 20 SWG wire

(B) 6 SWG wire

(C) 10 SWG wire

(D) 8 SWG wire

Q18. The ripple factor of a full-wave rectifier circuit compared to that of a half wave rectifier circuit without filter is

(A) half of that for a half 'wave rectifier

(B) less than half that for a half-wave rectifier circuit

(C) equal to that of a half wave rectifier

(D) more than half that for a half-wave rectifier Circuit

Q19. In a highly inductive circuit , a smali capacitance is added in series. Then the angle between applied voltage and resultant current will be

(A) increase

(B) decrease

(C) remains absolutely unaltered

(D) alter insignificantily

Q20. The inertia constant of the two machines which are not swinging together are M1 and M2. The equivale

(A) M1-M2

(B) M1+M2

(C) M1M2/(M1+M2)

(D) M1M2/(M1-M2)