# Insulation & Insulating materials - MCQs with Answers

## Insulation & Insulating materials - MCQs with Answers

Q1. The thickness of insulation provided on the conductor in the cable depends on which among the following factor?

a. Operating voltage.
b. Current to be carried.
c. Power factor.
d. Both (a) and (b).

ANSWER: a. Operating voltage.

Q2. The insulation resistance of a cable of length 10 km is 1M Ω . For a length of 100 km of the same cable, what will be the insulation resistance?

a. 1 M Ω
b. 10 M Ω
c. 0.1 M Ω
d. 0.01 M Ω

ANSWER: c. 0.1 M Ω

Q3. What is the main drawback of using paper as the insulating material?

a. Is hygroscopic
b. Has poor dielectric strength.
c. Has a very low insulation resistivity.
d. Has high capacitance.

ANSWER: a. Is hygroscopic

Q4. What is the limit of the conductor cross section when paper insulation is used?

a. 50 mm2
b. 250 mm2
c. 600 mm2
d. 1200 mm2

ANSWER: c. 600 mm2

Q5. What is the dielectric strength of impregnated paper?

a. 30 kV/mm
b. 20 kV/mm
c. 15 kV/mm
d. 5 kV/mm

ANSWER: a. 30 kV/mm

Q6. What is empire tape?

a. Impregnated paper
b. Vulcanised rubber
c. Enamel insulation
d. Varnished cambric

ANSWER: d. Varnished cambric

Q7. What is the percentage of added materials like sulphur, zinc lead etc in vulcanised rubber?

a. 5 – 10 %
b. 3 – 5 %
c. 4 – 8 %
d. 10 – 12 %