Match items in List-I with items in List-II most suitable.

List-I	List-II
a. LED	1. Heavy doping
b. Avalanche Photodiode	2. Coherent radiation
c. Tunnel diode	3. Spontaneous emission
d. LASER	4. Current gain

The forbidden energy gap between the valence band and conduction band will be least in case of

A. Metals

B. Semiconductors

C. Insulators

D. All of the above

For a NPN bipolar transistor, what is the main stream of current in the base region?

A. Drift of holes

B. Diffusion of holes

C. Drift of electrons

D. Diffusion of electrons

Assertion (A): A JFET can be used as a current source.
Reason (R): In beyond pinch off region the current in JFET is nearly constant.

A. Both A and R are true and R is correct explanation of A

B. Both A and R are true but R is not a correct explanation of A

C. A is true but R is false

D. A is false but R is true

For a P-N diode, the number of minority carriers crossing the junction depends on

A. Forward bias voltage

B. Potential barrier

C. Rate of thermal generation of electron hole pairs

D. None of the above