🔘. Copper as conductor for cables is used as
(a) annealed✔
(b) hardened and tempered
(c) hard drawn
(d) alloy with chromium
🔘. The insulating material should have
(a) low permittivity
(b) high resistivity✔
(c) high dielectric strength
(d) all of the above
🔘. 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✔
🔘 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
🔘. 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✔
🔘. It is difficult to maintain oil filled cables.
(a) Yes✔
(b) No
🔘. In capacitance grading a homogeneous dielectric is used.
(a) Yes
(b) No✔
🔘. In congested areas where excavation is expensive and inconvenient ‘draw in system’ of laying of underground cables is often adopted.
(a) Yes✔
(b) No
🔘. Natural rubber is obtained from milky sap of tropical trees.
(a) Yes✔
(b) No
🔘. Rubber is most commonly used insulation in cables.
(a) Yes✔
(b) No
🔘. Polyethylene has very poor dielectric and ageing properties.
(a) Yes
(b) No✔
🔘. The metallic sheath may be made of lead or lead alloy or of aluminium.
(a) Yes
(b) No✔
