Electrical Engineering Questions with Answer

Question # 1. The drive motor used in a mixer-grinder is a
(A) universal motor.
(B) induction motor.
(C) synchronous motor.
(D) dc motor.
Ans: (A) universal motor.

Question # 2. The direction of rotation of hysteresis motor is reversed by
 (A) Reversing supply lead
 (B) Shift shaded pole with respect to main pole
 (C) Either A or B
 (D) Neither A nor B
Ans: (B) Shift shaded pole with respect to main pole

Question # 3. Alternating current is measured by
(A) induction ammeter
(B) permanent magnet type ammeter
(C) electrostatic ammeter
(D) moving iron repulsion type voltmeter
Ans: (A) induction ammeter


Question # 4. A 3-phase, 400 votts, 50 Hz, 100 KW, 4 pole squirrel cage induction motor with a rated slip of 2% will have a rotor speed of
(A) 1500 rpm
(B) 1570 rpm
(C) 1530 rpm
(D) 1470 rpm
Ans: (D) 1470 rpm

Question # 5. The torque, in a _____________is proportional to the square of the armature current
(A) DC series motor
(B) stepper motor
(C) 2-phase servomotor
(D) DC shunt motor
 Ans:(A) DC series motor

Question # 6. Inverse definite minimum time lag relay is also called ___________
(A) pilot relay.
(B) differential relay.
(C) over current relay.
(D) directional overcurrent relay.
 Ans:(B) differential relay.


Question # 7. The scale of a rectifier instrument is
(A) linear
(B) non-linear
(C) either (a) or (b)
(D) neither (a) nor (b)
Ans: (A) linear

Question # 8. The synchronous reactance of the synchronous machine is ______________.
 (A) Ratio between open circuit voltage and short circuit current at constant field current
 (B) Ratio between short circuit voltage and open circuit current at constant field current
 (C) Ratio between open circuit voltage and short circuit current at different field current
 (D) Ratio between short circuit voltage and open circuit current at different field current
 Ans.  (A) Ratio between open circuit voltage and short circuit current at constant field current

Question # 9. If an instrument has cramped scale for larger values, then it follows
(A) square law
(B) logarithmic law
(C) uniform law
(D) none of the above
Ans: (B) logarithmic law


Question # 10. In a three phase transformer, if the primary side is connected in star and secondary side is connected in delta, what is the angle difference between phase voltage in the two cases.
(A) delta side lags by -30°.
(B) star side lags by -30°.
(C) star side leads by -30°.
(D) delta side leads by 30°.
 Ans: (D) delta side leads by 30°.