AP ECET EEE 2020-2

1. Two Generators A and B have 6-poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced emf's of generator A and B will be

A. 2:3
B. 3:1
C. 3:2
D. 1:3

Answer : B. 3:1
Explanation:-

2. DC Series motor is that which

A. has its field winding consisting of thick wire and less turns
B. has a poor torque
C. can be started easily without load
D. has almost constant speed

Answer : has its field winding consisting of thick wire and less turns
Explanation:-

3. In case of DC Shunt motors the speed is dependent on back emf only because

A. back emf is equal to armature drop
B. armature drop is negligible
C. flux is proportional to armature current
D. flux is practically constant in DC Shunt motors

Answer : D. flux is practically constant in DC Shunt motors
Explanation:-

4. In a DC Series motor, if the armature current is reduced by 50% the torque of the motor will be equal to

A. 100% of the previous value
B. 25% of the previous value
C. 50% of the previous value
D. 10% of the previous value

Answer : B. 25% of the previous value
Explanation:-

5. Which of the following method of speed control of DC machine will offer minimum efficiency?

A. Voltage control method
B. Field control method
C. Armature control method
D. Ward-Leonard method

Answer : C. Armature control method
Explanation:-

6. Which of the following are integrating instruments?

A. Ammeters
B. Voltmeters
C. Wattmeters
D. Amphere-hour and watt-hour meters

Answer : Amphere-hour and watt-hour meters
Explanation:-

7. For handling greater currents induction wattmeter are used in conjunction with

A. potential transformers
B. current transformers
C. power transformers
D. Resistors

Answer : B. current transformers
Explanation:-

8. The output of the thermocouple in the range of

A. Volts
B. Millivolts
C. Amperes
D. Milliamperes

Answer : B. Millivolts
Explanation:-

9. The temperature coefficient of thermistor transducer is

A. Negative
B. Positive
C. Zero
D. Infinite

Answer : A. Negative
Explanation:-

10. In an AC Circuit(sine wave) with R and L in series

A. Voltage across R and L 180 degree out of face
B. The voltage across R lags the voltage across L by 90 degrees
C. The voltage across R leads the voltage across L by 90 degrees
D. Voltage across R and L are in phase

Answer : B. The voltage across R lags the voltage across L by 90 degrees
Explanation:-