Low resistivity materials are used in__________? A. transformer, motor and generator windings B. transmission and distribution lines C. house wiringD. all above applications

Which of the following high resistance materials has the highest operating temperature ? A. Kanthal B. Manganin C. Nichrome D. Eureka

Platinum is used in_____________? A. electrical contacts B. thermocouple C. heating element in high temperature furnace D. grids of special purpose vacuum tubesE. all of the above

Steel wire is used as____________? A. overhead telephone wire B. earth wire C. core wire of ACSRD. all of the above

Carbon bearings are used under which of the following conditions ? A. Where lubrication is difficult or im-possible B. Where corrosive chemical action exists C. Where high temperature existsD. All of the above

Due to which of the following factors the brush wear rate is altered ? A. Speed of the machine B. Contact pressure C. Surface conditions of brush and commutator D. Excessive sparkingE. All of the above

The impurity atoms is semiconductors_____________? A. inject more charge carriersB. reduce the energy gap C. increase the kinetic energy of valence electrons D. all of the above

Carbon resistors are used extensively because they are____________? A. easy to make B. compact C. inexpensiveD. all of the above reasons

Which of the following are non-conductors of electricity? A. Non-metal solids except carbon B. Air and most other gases C. Pure water and liquids in general except mercuryD. All of the above

Carbon rods are used in wet and dry cells because_____________? A. carbon rod serves as conductor B. carbon can resist the attack of battery acidC. both (A) and (B) D. either (A) or (B)