Cable mcq part -3

1. The advantage of cables over overhead transmission lines is
(a) easy maintenance
(b) low cost
(c) can be used in congested areas
(d) can be used in high voltage circuits

Ans: c

2. The thickness of metallic shielding on cables is usually
(a) 0.04 mm
(b) 0.2 to 0.4 mm
(e) 3 to 5 mm
(d) 40 to 60 mm

Ans: a

3. Cables for 220 kV lines are invariably
(a) mica insulated
(b) paper insulated
(c) compressed oil or compressed gas insulated
(d) rubber insulated
(e) none of the above

Ans: c

14. Is a cable is to be designed for use on 1000 kV, which insulation would you prefer ?
(a) Polyvinyle chloride
(b) Vulcanised rubber
(c) Impregnated paper
(d) Compressed SFe gas
(e) none of the above

Ans: d

5. If a power cable and a communication cable are to run parallel the minimum distance
between the two, to avoid interference, should be
(a) 2 cm
(b) 10 cm
(c) 50 cm
(d) 400 cm

Ans: c

6. Copper as conductor for cables is used as
(a) annealed
(b) hardened and tempered
(c) hard drawn
(d) alloy with chromium
Ans: a

7. The insulating material should have
(a) low permittivity
(b) high resistivity
(c) high dielectric strength
(d) all of the above

Ans: d

8. The advantage of oil filled cables is
(a) more perfect impregnation
(b) smaller overall size
(c) no ionisation, oxidation and formation of voids
(d) all of the above
Ans: d

9. The disadvantage with paper as insulating material is
(a) it is hygroscopic
(6) it has high capacitance
(c) it is an organic material
(d) none of the above

Ans: a

10. The breakdown voltage of a cable depends on
(a) presence of moisture
(b) working temperature
(c) time of application of the voltage
(d) all of the above

Ans: d

11. It is difficult to maintain oil filled cables.
(a) Yes
(b) No

Ans: a

11. In capacitance grading a homogeneous dielectric is used.
(a) Yes
(b) No

Ans: b

12. In congested areas where excavation is expensive and inconvenient 'draw in system'
of laying of underground cables is often adopted.
(a) Yes
(b) No

Ans: a

13. Natural rubber is obtained from milky sap of tropical trees.
(a) Yes
(b) No

Ans: a

14. Rubber is most commonly used insulation in cables.
(a) Yes
(b) No

Ans: a

15. Polyethylene has very poor dielectric and ageing properties.
(a) Yes
(b) No
Ans: b

16. The metallic sheath may be made of lead or lead alloy or of aluminium.
(a) Yes
(b) No
Ans: b