15- An ideal voltage source should have
(A) Zero source resistance.
(B) Infinite source resistance.
(C) Large value of e.m.f.
(D) Zero e.m.f.
16- The single-phase induction motor that can be used on both d.c. and a.c. circuit is
(A) Hysteresis motor.
(B) Universal motor.
(C) Reluctance induction motor.
(D) Repulsion induction motor.
17- A multivibrator produces
(A) Pure sine waves.
(B) Square waves
(C) Distorted sine waves
(D) Sawtooth waves
18- The maximum number of buses in a power system are
(A) PV buses.
(B) PQ buses.
(C) Slack buses.
(D) Infinite buses.
19- Dummy coils are provided in d.c. generators
(A) To reduce eddy current losses.
(B) To amplify voltage.
(C) To enhance flux density.
(D) To mechanically balance the rotor.
20- The phase relation between the arc voltage and arc current is
(A) They are in phase.
(B) The arc voltage lags the arc current by 90°.
(C) The arc voltage leads the arc current by 90°.
(D) The arc voltage leads the arc current by 45°.
21- The unit protection scheme provides
(A) Primary protection.
(B) Back-up protection.
(C) Simultaneous protection.
(D) Remote protection.
22- A memory in which information is shifted one position at a time when one clock pulse is applied is a
(A) Counter
(B) Flip flop
(C) Shift register
(D) Multiplexer.
23- Which winding is preferred in d.c. generators to generate large currents?
(A) Lap winding
(B) Fractional winding.
(C) Wave winding
(D) Reprogressive wave winding.
24- The operating point of a measuring current transformer is
(A) Near the knee point.
(B) Near the elbow point.
(C) Near the ankle point.
(D) Near the shoulder point.
25- A point in the power system where no protection is provided is called a
(A) Vulnerable spot.
(B) Weak spot.
(C) Fault spot.
(D) Blindspot.
26- With a JK master flip-flop, the master is clocked when the clock is
(A) Low
(B) High
(C) Either low or high
(D) Zero
27- The presence of earth wire in case of overhead lines
(A) Increases the line capacitance.
(B) Decreases the line capacitance.
(C) Increases the line inductance.
(D) Decreases the line inductance.
ANSWERS:
15-(A), 16-(B), 17-(B), 18-(B), 19-(D), 20-(A), 21-(A), 22-(C), 23-(A), 24-(A), 25-(D), 26-(B), 27-(A)