Underground Cable MCQ

1. Dielectric strength of rubber is around

  1. 5 kV/mm
  2. 15 kV/mm
  3. 30 kV/mm
  4. 200 kV/mm

Answer
Answer. c

2. In single core cables armouring is not done to

  1. avoid excessive sheath losses
  2. make it flexible
  3. either of the above
  4. none of the above

Answer
Answer. a

3. The minimum dielectric stress in a cable is at

  1. armour
  2. bedding
  3. conductor surface
  4. lead sheath

Answer
Answer. d

4. Conduit pipes are normally used to protect _____ cables.

  1. unsheathed cables
  2. armoured
  3. PVC sheathed cables
  4. all of the above

Answer
Answer. a

5. _______ cables are used for 132 kV lines.

  1. High tension
  2. Super tension
  3. Extra high tension
  4. Extra super voltage

Answer
Answer. d

6. In case of three core flexible cable, the colour of the neutral is

  1. blue
  2. black
  3. brown
  4. none of the above

Answer
Answer. a

7. The current carrying capacity of cables in D.C. is more than that in A.C. mainly due to

  1. absence of harmonics
  2. non-existence of any stability limit
  3. smaller dielectric loss
  4. absence of ripples

Answer
Answer. c

8. In a cable immediately above metallic sheath, _____ is provided.

  1. earthing connection
  2. bedding
  3. armouring
  4. none of the above

Answer
Answer. b

9. The insulating material for cables should

  1. be acid proof
  2. be non-inflammable
  3. be non-hygroscopic
  4. have all above properties

Answer
Answer. d

10. The bedding on a cable consists of

  1. hessian cloth
  2. jute
  3. any of the above
  4. none of the above

Answer
Answer. c

11. The thickness of the layer of insulation on the conductor, in cables, depends upon

  1. reactive power
  2. power factor
  3. voltage
  4. current carrying capacity

Answer
Answer. c

12. Empire tape is

  1. varnished cambric
  2. vulcanised rubber
  3. impregnated paper
  4. none of the above

Answer
Answer. a

13. Which of the following insulation is used in cables?

  1. Varnished cambric
  2. Rubber
  3. Paper
  4. Any of the above

Answer
Answer. d

14. Which of the following protects a cable against mechanical injury?

  1. Bedding
  2. Sheath
  3. Armouring
  4. None of the above

Answer
Answer. c

15. The insulating material for a cable should have

  1. low cost
  2. high dielectric strength
  3. high mechanical strength
  4. all of the above

Answer
Answer. d

16. _____ is done just above the bedding’s surface.

  1. Metallic sheathing
  2. Serving
  3. Insulation
  4. Armouring

Answer
Answer. d

17. In comparison to overhead transmission, in underground systems

  1. Voltage loss is less
  2. Fault correction is easier
  3. Value of charged current is less
  4. Initial cost of the system is low

Answer
Answer. a

18. Which of the following may not be the possible reason for open circuit fault in the cable?

  1. Due to the rupture of electric insulation
  2. Due to excessive pressure
  3. Due to the breaking of core of cable
  4. Due to swift turn

Answer
Answer. a

19. The effect of bonding the cables is to

  1. Increase effective resistance and inductance
  2. Increase effective resistance but reduce inductance
  3. Decrease effective resistance and inductance
  4. Decrease effective resistance but increase inductance

Answer
Answer. b

20. The insulation resistance of a cable of length 10 km is 1 Mega ohm. Its resistance for 50 km length will be

  1. 1 Mega ohm
  2. 5 Mega ohm
  3. 0.2 Mega ohm
  4. 50 Mega ohm

Answer
Answer. c

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