IOCL Junior Operator MCQ Part-8 || IOCL Junior Operator General Science Questions and Answers61. What material is used for the metallic screen in H-type cables?1 . Copper foil 2 . Aluminium foil 3 . Lead foil 4 . Steel foil Answer and SolutionAnswer: "Aluminium foil "The metallic screen in H-type cables usually consists of a perforated aluminium foil. Discuss62. What is the primary advantage of the metallic screen in H-type cables?1 . It eliminates air pockets in the dielectric 2 . It increases the heat dissipating power of the cable 3 . It minimizes core-to-core breakdown 4 . It makes bending easier Answer and SolutionAnswer: "It increases the heat dissipating power of the cable "The metallic screen in H-type cables increases the heat dissipating power of the cable. Discuss63. What is the main difference between H-type and S.L. type cables?1 . The presence of an overall lead sheath 2 . The type of insulation used 3 . The number of cores 4 . The thickness of the metallic screen Answer and SolutionAnswer: "The presence of an overall lead sheath "The main difference is that S.L. type cables have a separate lead sheath around each core insulation, while H-type cables have an overall lead sheath. Discuss64. What is one advantage of S.L. type cables over H-type cables?1 . Better heat dissipation 2 . Higher voltage capacity 3 . Lower manufacturing cost 4 . Easier bending due to the absence of an overall lead sheath Answer and SolutionAnswer: "Easier bending due to the absence of an overall lead sheath "One advantage of S.L. type cables over H-type cables is that bending becomes easier due to the elimination of the overall lead sheath. Discuss65. Why is the voltage limit for solid type cables 66 KV?1 . Due to the risk of lead sheath damage 2 . Due to the risk of moisture ingress 3 . Due to the risk of void formation 4 . All of the above Answer and SolutionAnswer: "All of the above "The voltage limit for solid type cables is 66 KV due to the risk of lead sheath damage, moisture ingress, and void formation. Discuss66. What happens to the cable compound when a solid cable carries a load?1 . It contracts 2 . It expands 3 . It solidifies 4 . It liquefies Answer and SolutionAnswer: "It expands "When a solid cable carries a load, its conductor temperature increases, causing the cable compound to expand. Discuss67. What can happen to the lead sheath when the load on a solid cable decreases?1 . It can stretch 2 . It can contract 3 . It can crack 4 . It can form a partial vacuum Answer and SolutionAnswer: "It can form a partial vacuum " When the load on a solid cable decreases, the conductor cools, forming a partial vacuum within the cable sheath. This can cause moisture to be drawn into the cable if there are pinholes in the lead sheath. Discuss68. Why are solid type cables unreliable for voltages beyond 66 KV?1 . Due to high manufacturing costs 2 . Due to the presence of voids 3 . Due to poor heat dissipation 4 . Due to mechanical damage Answer and SolutionAnswer: "Due to the presence of voids "Solid type cables are unreliable for voltages beyond 66 KV because there is a danger of insulation breakdown due to the presence of voids. Discuss69. What is the primary reason for using pressure cables for voltages greater than 66 KV?1 . To increase the cable’s mechanical strength 2 . To improve heat dissipation 3 . To eliminate voids in the insulation 4 . To reduce manufacturing costs Answer and SolutionAnswer: "To eliminate voids in the insulation "Pressure cables are used for voltages greater than 66 KV to eliminate voids in the insulation, which helps prevent breakdown. Discuss70. What are the two common types of pressure cables?1 . Oil filled and gas pressure cables 2 . Belted and H-type cables 3 . Single-core and multi-core cables 4 . Solid type and screened cables Answer and SolutionAnswer: "Oil filled and gas pressure cables "The two common types of pressure cables are oil filled cables and gas pressure cables. Discuss123456789
