Q.1
Thermonic emission occurs in
Q.2
High resistivity materials are used in
Q.3
Low resistivity materials are used in
Q.4
By increasing impurity content in the metal alloy the residual resistivity always
Q.5
Carbon bearings are used under which of the following conditions ?
Q.6
Is an element used in semiconductors whose atoms have three valence electrons.
Q.7
The coils of D.C. motor starter are wound with wire of
Q.8
The co-ordination number of a simple cubic structure is
Q.9
The conduction of electricity, in semiconductors, takes place due to movement of
Q.10
In conductors conduction of electricity takes place due to movement of
Q.11
The converse of hardness is known as
Q.12
Which of the following resistive materials has the lowest temperature co-efficient of resistance ?
Q.13
The resistivity of a metal is a function of temperature because
Q.14
_______ is a hard solder.
Q.15
Copper, even though costly, finds use in the windings of electrical machines because
Q.16
_______ has zero temperature co-efficient of resistance.
Q.17
Which of the following is a semiconductor material ?
Q.18
Most of the common metals have _________ structure.
Q.19
Which of the following materials does not have covalent bonds ?
Q.20
For germanium the forbidden energy gap is
0 h : 0 m : 1 s