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.Management Sciences
Category: Electrical Engineering Materials
The conductivity of a metal is determined by____________?
0
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
In thermocouples which of the following pairs is commonly used ?
A. Copper-constantan
B. Aluminium-tin
C. Silver-German silver
D. Iron-steel
Spark plug makes use of which of the following materials for insulation ?
A. Porcelain
B. Slate
C. Asbestos
D. Glass
The converse of hardness is known as______________?
A. malleability
B. toughness
C. softness
D. none of the above
The coils of D.C. motor starter are wound with wire of_______________?
A. copper
B. kanthal
C. manganin
D. nichrome
In conductors conduction of electricity takes place due to movement of_______________?
A. electrons only
B. positive ions only
C. negative ions only
D. positive and negative ions
E. none of the above
Which of the following factors affect resistivity of metals ?
A. Age hardening
B. Alloying
C. Temperature
D. Cold work
E. All of the above
For a particular material the Hall coefficient was found to be zero. The material is______________?
A. insulator
B. metal
C. intrinsic semiconductor
D. none of the above
Which of the following resistive materials has the lowest temperature co-efficient of resistance ?
A. Nichrome
B. Constantan
C. Kanthal
D. Molybdenum
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