1. In cables the charging current
(a) lags the voltage by 90°
(b) leads the voltage by 90°
(c) lags the voltage by 180°
(d) leads the voltage by 180° Answer ⇓
2. In the cables, sheaths are used to
(a) prevent the moisture from entering the cable
(b) provide enough strength
(c) provide proper insulation
(d) none of the above
Answer ⇓
3. The inter-sheaths in the cables are used to
(a) minimize the stress
(b) avoid the requirement of good insulation
(c) provide proper stress distribution
(d) none of the above
Answer ⇓
4. The electrostatic stress in underground cables is
(a) same at the conductor and the sheath
(b) minimum at the conductor and maximum at the sheath
(c) maximum at the conductor and minimum at the sheath
(d) zero at the conductor as well as on the sheath
Answer ⇓
5. In a cable the voltage stress is maximum at
(a) sheath
(b) insulator
(c) surface of the conductor
(d) core of the conductor
Answer ⇓
6. The insulating material used in cable should have
(a) low permittivity
(b) high resistivity
(c) high dielectric strength
(d) all of the above
Answer ⇓
7. Insulated cables are usually rated by their
(a) operating voltage.
(b) operating voltage and highest operating temperature.
(c) current carrying capacity
(d) cost.
Answer ⇓
8. The insulating material for a cable should have
(a) low cost
(b) high dielectric strength
(c) high mechanical strength
(d) all of the above
Answer ⇓
9. Which of the following protects a cable against mechanical injury?
(a) Bedding
(b) Sheath
(c) Armouring
(d) None of the above
Answer ⇓
10. Which of the following insulation is used in cables?
(a) Varnished cambric
(b) Rubber
(c) Paper
Any of the above
Answer ⇓
11. Empire tape is
(a) varnished cambric
(b) vulcanised rubber
(c) impregnated paper
(d) none of the above
Answer ⇓
12. The thickness of insulation layer of a cable depends upon
(a) reactive power
(b) voltage
(c) current carrying capacity
(d) all of the above
Answer ⇓
13. The current carrying capacity of cables in D.C. is more than that in A.C. mainly due to
(a) absence of harmonics
(b) non-existence of any stability limit
(c) smaller dielectric loss
(d) absence of ripples
Answer ⇓
14. In case of three core flexible cable the colour of the neutral is
(a) blue
(b) black
(c) brown
(d) none of the above
Answer ⇓
15. At which part of a cable dielectric stress minimum?
(a) armour
(b) bedding
(c) conductor
(d) lead sheath