Electrical engineering previous Year question ISRO | MCQ Question |Previous Years Questions

Electrical Engineering Questions MCQ Questions

Q1. A Meter has a full scale deflection of 90" at a current of 1A. The response of the meter is square law. Assuming spring control, the current for a deflection at 45" will be
  • (A) 0.25
  • (B) 0.50
  • (C) 0.707
  • (D) 0.67

Q2. A Single-phase Energy meter is operating on 230V, 50 Hz supply with a load of 20A for two hours at UPF. The meter makes 1380 revolutions in that period. The meter constant
  • (A) 695 rev/kWh
  • (B) 150 rev/kWh
  • (C) 0.15 rev/kWh
  • (D) 1/150 rev/kWh

Q3. In case of power measurements by two wattmeter method in a balanced 3-phase system
With pure inductive load
  • A) both wattmeters will indicates the same 
  • (B) both wattmeters will indicate zero value but with opposite signs
  • (C)both the wattmeters will indicate the same value same sign
  • (D) one wattmeter will indicate zero and the other will indicate some non-Zero value

Q4. It is required to measure temperature in the range of 1300°C to 1500⁰C. The most suitable thermocouple to be used as transducer would be
  • (A)Chromel constantan
  • (B)lron-constantan
  • (C)Chromel - alumel
  • (D) Platinum-rhodiumn

Q5. Which dc motor will have highest percentage increase in input current for given percentage increase in torque
  • (A) Series motor
  • (B) shunt motor
  • (C) cumulatively compound motor
  • (D) separately excited motor

Q6. In a three phase delta transfomer, one phase burns up. The transformer will supply
  • (A) 57.7% of its rating
  • (B) zero output
  • (C) 63% of its output rating
  • (D) at full output rating

Q7. In an auto transtformer, power is transferred through
  • (A) conduction process alone
  • (B) induction process alone
  • (C) both conduction and induction
  • (D) mutual coupling processes

Q8. Buchholz relay is a
  • (A) voltage sensitive device
  • (B) current sensitive device
  • (C) frequency sensitive device
  • (D) gas actuated device

Q9. In Scott connection, if the ratio of the main transformer is k, then the teaser transformner has transformation ratio of
  • (A) 2k/N3
  • (B) 3k /2
  • (C)K/N3
  • (D) K/2

Q10. With core type transformers, the limbs are stepped so as to
  • (A) reduce the iron material and therefore iron loss
  • (B) provide better cooling
  • (C) reduce the conductor material and therefore I²R loss
  • (D) providee more mechanical strength to the core

Q11. In alternator, during hunting when the speed becomes super synchronous, the damper bars develop
  • (A) reluctance torque
  • (B) pseudo-stationary torque
  • (C) eddy current torque
  • (D) induction generator torque

Q12. It is never advisable to connect a stationary alternator to live bus-bar because it
  • (A) is likely to run as a synchronous motor
  • (B)will get short circuited
  • (C) will decrease bus-bar voltage though momentarily
  • (D) will disturbs generated emfs of other alternators connected in parallel

Q13. Under no load condition, the angle between the induced voltage and the supply voltage in synchronous motor is
  • (A) zero degree
  • (B) 45⁰
  • (C) 90⁰
  • (D) 180⁰

Q14. Synchronous motors are not self starting because
  • (A) Stator not used
  • (B) Starting winding not provided
  • (C) There is no slip
  • (D) The direction of instantaneous torque on the rotor reverses after half cycle

Q15. A three phase induction motor running at 1440 rpm on rated supply will run at the following rpm when fuse of one phase gets burnt
  • A) 1440
  • B) 1380
  • (C) 1500
  • (D) zero

Q16. Dispersion coefficient a is the ratio of
  • (A) magnetizing current to supply voltage
  • (B) open circuit voltage to short circuit current for the same excitement
  • (D) short circuit current to magnetizing
  • (C) magnetizing current to ideal short Circuit current

Q17. In the circle diagram for a 3-phase induction motor, the diameter of the circle is determined by
  • (A) total stator current
  • (B) exciting current
  • (C) rotor current
  • (D) rotor current referred to stator

Q18. While conducting short-circuit test on a transformer the following side is short circuited
  • A) High voltage side
  • (B) low voltage side
  • (C) primary side
  • (D) secondary side

Q19. Thrust developed by a linear induction motor dependsson
  • (A) synchronous speed
  • (B) rotor input
  • (C) rotor input and synchronous speed
  • (D) number of poles

Q20. The crawling in an induction motor is caused by
  • (A) improper design of machine
  • (B) low voltage supply
  • (C) high loads
  • (D) harmonics developed in the motor

Q21. The main disadvantages of using short pitch winding in alternators is that it
  • (A) reduces harmonics in the generated 
  • (B) reduces the total voltage around the voltage armature coils
  • (C) produces asymmetry in the three phase windings
  • (D) Increases Cu of end connections.

Q22. Armature reaction in an alternator mainly affects
  • (A) rotor speed
  • (B) terminal voltage per phase
  • (C) frequency of Armature current
  • (D) Generated voltage per phase

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