Instrumentation & Control Cables Quiz 

 

1. Copper as conductor for cables is used as 

Annealed

Hardened and tempered

Hard drawn

Alloy with chromium

Answer: Annealed

 

2. The breakdown voltage of a cable depends on 

Presence of moisture

Working temperature

Time of application of the voltage

All of the above

Answer: All of the above

 

3. The inner-sheath in the cables are used to 

Minimise the stress

Avoid the requirement of good insulation

Provide proper stress distribution

Any of the above

None of the above

Answer: Provide proper stress distribution

 

4. The material for armouring on cable is usually 

Galvanised steel flat strip

Galvanised steel wire

Any of the above

Answer: Any of the above

 

5. The insulating material for cables should 

Be acid proof

Be non-inflammable

Be non-hygroscopic

All above properties

Answer: All above properties

 

6. The insulating material for a cable should have 

Low cost

High dielectric strength

High mechanical strength

All of the above

Answer: All of the above

 

7. Which of the following protects a cable against mechanical injury 

Bedding

Sheath

Armouring

None of the above

Answer: Armouring

 

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

Reactive power

Power factor

Voltage

Current carrying capacity

Answer: Voltage

 

9. Low tension cables are generally used up to 

200 V

500 V

700 V

1000 V

Answer: 1000 V

 

10. PVC stands for 

Polyvinyl chloride

Post varnish conductor

Positive voltage conductor

None of the above

Answer: Polyvinyl chloride

 

11. In the cables, the location of fault is usually found out by comparing 

The resistance of the conductor

The inductance of conductors

The capacitances of insulated conductors

All above parameters

Answer: The capacitances of insulated conductors

 

12. If the length of a cable is doubled, its capacitance

Becomes one-fourth

Becomes one-half

Becomes double

Bemains unchanged

Answer: Becomes double

 

13. The breakdown of insulation of the cable can be avoided economically by the use of 

Inner-sheaths

Insulating materials with different dielectric constants

Both

Answer: Both

 

14. In a cable the voltage stress is maximum at 

Sheath

Insulator

Surface of the conductor

Core of the conductor

Answer: Core of the conductor

 

15. The thickness of metallic shielding on cables is usually 

0.04 mm

0.2 to 0.4 mm

3 to 5 mm

40 to 60 mm

Answer: 0.04 mm

 

16. If a power cable and a communication cable are to run parallel the minimum distance between the two, to avoid interference, should be 

2 cm

10 cm

50 cm

400 cm

Answer: 50 cm

 

17. Polyethylene has very poor dielectric and ageing properties. 

Yes

No

Answer: No

 

18. With the rise in temperature, the insulation resistivity of a cable 

Remain unchanged

Decreases linearly

Increases linearly

Reduces exponentially

Answer: Reduces exponentially

 

19. The current carrying capacity of cables in DC is more than that in AC. It is mainly due to 

Smaller hysteresis losses

Absence of harmonics

Absence of ripples

Answer: Smaller hysteresis losses

 

20. The power factor of an open ended cable can be improved by 

Increasing the capacitance

Decreasing the capacitance

Increasing the insulation resistance

Increasing the conductor resistance

Answer: Increasing the insulation resistance