81. The carbon percentage is least in A. low carbon steel B. wrought iron C. cast iron D. malleable iron Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
82. Addition of 0.3 to 4.5% silicon to iron __________ the electrical resistivity of iron. A. Increases B. Decreases C. Does not change D. Change Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
83. Due to which of the following reasons aluminium does not corrode in atmosphere ? A. Aluminium is a noble metal B. Atmospheric oxygen can only diffuse very slowly through the oxide layer which is formed on the surface of aluminium C. No reaction with oxygen occurs ft Any of the above D. All of the above Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
84. In thermocouples which of the following pairs is commonly used ? A. Copper-constantan B. Aluminium-tin C. Silver-German silver D. Iron-steel Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
85. If the resistance of a conductor does not vary in accordance with Ohm’s law it is known as A. non-linear conductor B. reverse conductor C. bad-conductor D. non-conductor Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
86. Surface resistance of an insulating material is reduced due to the A. Smoky and dirty atmosphere B. Humidity in the atmosphere C. Both A and B D. Neither A nor B Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option C No explanation is given for this question Let's Discuss on Board
87. Due to which of the following fact, in India, aluminium is replacing copper ? A. Aluminium is more ductile and malleable than copper B. Aluminium is available in plenty, cheaper and lighter than copper C. Aluminium has lower resistivity than that of copper D. Aluminium has less temperature co-efficient than copper Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option B No explanation is given for this question Let's Discuss on Board
88. Which of the following is an advantage of stranded conductor over equivalent single conductor ? A. Less liability to kink B. Greater flexibility C. Less liability to break D. All of the above Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
89. The conductivity of a metal is determined by A. The electronic concentration and the mobility of the free electrons B. The number of valence electrons per atom C. Either A or B D. None of the above Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option A No explanation is given for this question Let's Discuss on Board
90. Steel wire is used as A. Overhead telephone wire B. Earth wire C. Core wire of ACSR D. All of the above Answer & Solution Discuss in Board Save for Later Answer & Solution Answer: Option D No explanation is given for this question Let's Discuss on Board
