The breakdown of insulation of the cable can be avoided economically by the use of___________?
		A. inter-sheaths
B. insulating materials with different dielectric constants
C. both (A) and (B)
D. none of the above
		A. inter-sheaths
B. insulating materials with different dielectric constants
C. both (A) and (B)
D. none of the above
		A. varnished cambric
B. vulcanised rubber
C. impregnated paper
D. none of the above
		A. prevent the moisture from entering the cable
B. provide enough strength
E. provide proper insulation
D. none of the above
		A. armour
B. bedding
C. conductor surface
D. lead sheath
		A. composite
B. porous
C. homogeneous
D. hygroscopic
		A. be acid proof
B. be non-inflammable
C. be non-hygroscopic
D. have all above properties
		A. insulation may melt due to higher temperature
B. skin effect dominates on the conductor
C. of corona loss between conductor and sheath material
D. there is a danger of breakdown of insulation due to the presence of voids