FUNCTION -5 (ELECTRICAL)

SECTION – 2

1. What happens to the strength of electromagnetic field when current passing through an inductor is halved?
   1. ¼
   2. ½
   3. 2
   4. 4

ANS.: A

2. To prevent the race of DC series, motor what arrangement should make?
   1. Always start at heavy load
   2. Use a strong series weak shunt compound DC motor
   3. Use a weak series strong shunt compound DC motor
   4. All

ANS.: A

3. If thyristor is used in place of starter
   1. Cost decreases
   2. Space decreases
   3. As load increases frequency increases uniformly
   4. Maintenance decreases

ANS.: A,B,D

4. For incoming generator which of the statements are true?
   1. If Incoming generator voltage is increased, then it will have motoring effect.
   2. If voltage is decreased, then it will cause black out.
   3. If frequency do not match, then it will run slowly.
   4. If frequency do not match, then will run fast.

ANS.: B

5. Pure inductive power is called
   1. Reactive power
   2. True power
   3. Set power
   4. Apparent power

ANS.: A

6. Zener diode is used as
   1. Voltage regulator
   2. Rectifier
   3. Reducer
   4. Transformer

ANS.: A

7. With the help of which of the following, pressure to electrical signal conversion takes place?
   1. Transducer
   2. Tactile sensor
   3. Shunt Reactor
   4. Shunt generator

1. Only i
2. I & ii
3. Only iv
4. ii & iv

ANS.: A

8. Which statement is true in relation to AUTO TRANSFORMER?
   1. More effective than conventional transformer
   2. Any fractional voltage can be applied
   3. Can be used both for A.C and D.C
   4. Low cost

ANS.: A,B,D

9. For a turbo electric propulsion generator which can be fitted?
   1. Co2 system
   2. Moisture something
   3. Stator winding temperature sensor
   4. All

ANS.: D

10. Class B AMPLIFIER advantage?
    1. Very low standing bias current.
    2. Negligible power consumption without signal.
    3. More efficient than Class A.
    4. Can be used for much more powerful outputs than class A

ANS.: A,B,C,D

11. How is natural cooling of transformer done?
    1. Air blast
    2. Oil cooling
    3. Water cooling
    4. None

ANS.: A

12. Atoms are bonded by?
    1. Valence electrons
    2. Neutron
    3. Proton
    4. Not known

ANS.: A

13. If in an electromagnetic coil current is ½ then its energy stored will be?
    1. ¼
    2. ½
    3. Twice
    4. No change

ANS.: A

14. For half wave rectifier ripple factor is?
    1. 41
    2. 21
    3. 131
    4. 51

ANS.: B

15. To satisfy amplification, transistor amplifier must satisfy?
    1. Forward biasing of output circuit.
    2. Reverse biasing in input circuit.
    3. Operate at set point
    4. All

ANS.: C

16. Which of the following are true for Thermistors
    1. Thermistors are semiconductors devices
    2. In a Positive temperature coefficient (PTC) thermistors, resistance increases with temperature increase
    3. –ve temperature coefficient (NTC) thermistors, can be used as replacement of fuse.
    4. NTC thermistors are generally used for monitoring coolant and engine lube oil temp in automobiles.

ANS.: A,B,D

17. Which trip is present in emergency generator?
    1. Over voltage trip
    2. Under voltage trip
    3. Over speed trip
    4. None

ANS.: C

18. NER- what is true for high voltage circuit?
    1. To limit max load current
    2. Neutral earth resonance
    3. Main switchboard earthed
    4. Not known

ANS.: A

19. Which of the following is not self-starting motor?
    1. Squirrel cage motor
    2. Synchronous motor
    3. Induction motor
    4. Split phase motor

ANS.: B

20. In capacitor, energy stored is?
    1. Potential energy
    2. Electrostatic energy
    3. Kinetic
    4. Not known

ANS.: B

21. For t/c, leak current in P-N diode is produced by?
    1. Heat energy
    2. Chemical energy
    3. Barrier potential
    4. Not known

ANS.: A

22. Motor overhaul is to be done which statements are true?
    1. Stator should be isolated
    2. Tag on overall ship
    3. Both
    4. None

ANS.: A

23. Electric motor stator- true statements?
    1. Generator used only with slip rings motors.
    2. convertor can be used as starter.
    3. Auto transformer act as rheostat starter
    4. Not known

ANS.:  B,C

24. Which statement is true in relation to AUTO TRANSFORMER?
    1. More effective than conventional transformer
    2. Can be used both for A.C and D.C
    3. Less excitation needed.
    4. Small size

ANS.: A,C,D

25. Squirrel cage used in synchronous motor for?
    1. Improving power factor
    2. Uniform balancing
    3. Just for starting
    4. Not known

ANS.: C

26. Which of the following will prevent a DC generator from becoming motorized?
    1. Overcurrent relay
    2. Motorization trip
    3. Reverse power relay
    4. Reverse current relay

ANS.: D              

27. For leading power circuits which of the following can be used?
    1. Shunt capacitors only
    2. Shunt reactors only
    3. Either shunt capacitors or shunt reactors
    4. Neither shunt capacitors nor shunt reactors

ANS.: B                               

28. To repair a small electric motor which was submerged in saltwater, you should
    1. Wash it with fresh water and apply an external source of heat.
    2. Renew the windings
    3. Send it ashore to an approved service facility
    4. Rinse all electrical parts with a carbon tetrachloride cleaning solvents and then blow dry the motor with compressed air

ANS.: A                 

29. An operating characteristic appearing on the name plates of shipboard AC motor is _____
    1. Type of windings
    2. Input kw
    3. Temp rise
    4. Locked rotor torque

ANS.: C

30. Fuses replaced in series with thermal trip type circuit breakers are used for?
    1. Time delay protection
    2. Short circuit protection
    3. Short duration surge protection
    4. Sustained overload protection

ANS.: B