1. . Shape of a crystal is simple cubic when one atom lies at its:
(A) Four corners
(B) Eight corners
(C) Six corners
(D) Five corners
2. . Band theory of solids has explained the behaviour of:
(A) Insulators
(B) Conductors
(C) Semiconductors
(D) All of these
3. . Which of the following has the greatest energy gap:
(A) Insulator
(B) Conductor
(C) Semiconductor
(D) All of these
4. . The substances having intermediate values of resistivity are called:
(A) Conductor
(B) Insulator
(C) Semiconductor
(D) All of these
5. . An N-type semiconductor is obtained by adding impurity:
(A) Antimony
(B) Aluminium
(C) Boron
(D) Indium
6. . A P-type semiconductor is obtained by adding impurity in the form of:
(A) Indium
(B) Antimony
(C) Phosphorus
(D) Cobalt
7. . A forward biased diode has resistance:
(A) Zero
(B) Infinite
(C) Low
(D) High
8. . A semiconductor diode conducts only when it is:
(A) Forward biased
(B) Reverse biased
(C) Not biased
(D) All of these
9. . The reverse current through a semiconductor diode is due to:
(A) Minority carriers
(B) Majority carriers
(C) Holes
(D) Electrons
10. . Photovoltaic cell is a device which converts:
(A) Light into electrical energy
(B) Light into chemical energy
(C) Chemical energy into light
(D) Light into sound