AP Mocktest 2020-1

1. Diversity factor is the ratio of _____

A. sum of maximum demands of consumers/systems maximum demand
B. maximum demand of consumers/average demand
C. demand of all consumers/average demad
D. Average demad / system maximum demand

Answer : sum of maximum demands of consumers/systems maximum demand
Explanation:-

2. Armature reaction in a synchronous motor at rated voltage and zero power factor (lead) is _____

A. magnetising
B. cross magnetising
C. both magnetising and cross-magnetising
D. demagnetising

Answer : demagnetising
Explanation:-

3. In a three phase induction motor, the starting torque will be maximum when

A. S=R2/X2
B. R2=X2
C. R2=X2^2
D. R2=X2/S

Answer : A. S=R2/X2
Explanation:-

4. Trapezoidal speed-time curve pertains to _____

A. main line service
B. urban service
C. suburban service
D. urban/suburban service

Answer : A. main line service
Explanation:-

5. If the differential and common mode gains of a differential amplifier are 50 and 0.2 respectively, then the CMRR will be________

A. 10
B. 49.8
C. 50.2
D. 250

Answer : B. 49.8
Explanation:- We know that CMMR = Ad/Ac 20 log (CMMR) = 20 log Ad - 20 log Ac = 50 - 0.2 = 49.8 dB.

6. The major cause of creeping in an energy meter is ________

A. over compensation for friction
B. mechanical vibrations
C. excessive voltage across the potential coil
D. stray magnetic fields

Answer : A. over compensation for friction
Explanation:-

7. If one of the control springs of a permanent magnet moving coil ammeter is broken then ,when connected it will read____

A. zero
B. half of the correct value
C. twice the correct value
D. an infinite value

Answer : A. zero
Explanation:-

8. The speed time curve for urban service has no _______

A. coasting period
B. free running period
C. breaking period
D. acceleration period

Answer : free running period
Explanation:-

9. The RRRV depends upon the _______

A. type of the circuit breaker
B. capacitance of the system only
C. inductance of the system only
D. inductance and capacitance of the system

Answer : inductance and capacitance of the system
Explanation:-

10. An ideal synchronous motor has no starting torque because the ______

A. rotor is made up of salient poles
B. relative velocity between the stator and the rotor mmfs is zero
C. relative velocity between the stator and rotor mmfs is not zero
D. rotor winding is highly reactive

Answer : relative velocity between the stator and the rotor mmfs is zero
Explanation:-