# 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
• 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
• (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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