The conduction of electricity, in semiconductors, takes place due to movement of______________?
(A) positive ions only
(B) negative ions only
(C) positive and negative ions
(D) electrons and holes
For a hole which of the following statements is incorrect ?
(A) Holes can exist in certain semiconductors only
(B) Holes can exist in any material including conductors
(C) Holes may constitute an electric current
(D) Holes can be considered as a net positive charge
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
Superconducting metal in super conducting state has relative permeability of________________?
(A) zero
(B) one
(C) negative
(D) more than one
Which of the following factors affect resistivity of metals ?
(A) Age hardening
(B) Alloying
(C) Temperature
(D) Cold work
(D) All of the above
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)
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
(D) none of the above
Effect of moisture on the insulating materials is to________________?
(A) decrease dielectric constant
(B) decrease dielectric strength
(C) decrease insulation resistance
(D) increase dielectric loss
(D) all of the above
The forbidden gap in an insulator is________________?
(A) large
(B) small
(C) nil
(D) any of the above
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