The cause of the potential barrier in a P-N diode is

(1) Depletion of positive charges near the junction

(2) Concentration of positive charges near the junction

(3) Depletion of negative charges near the junction

(4) Concentration of positive and negative charges near the junction

Which of the following statements is not true

(1) The resistance of intrinsic semiconductors decrease with increase of temperature

(2) Doping pure with trivalent impurities give P-type semiconductors

(3) The majority carriers in N-type semiconductors are holes

(4) A PN-junction can act as a semiconductor diode

The dominant mechanisms for motion of charge carriers in forward and reverse biased silicon P-N junctions are

(1) Drift in forward bias, diffusion in reverse bias

(2) Diffusion in forward bias, drift in reverse bias

(3) Diffusion in both forward and reverse bias

(4) Drift in both forward and reverse bias

When the P end of P-N junction is connected to the negative terminal of the battery and the N end to the positive terminal of the battery, then the P-N junction behaves like 

(1) A conductor                       

(2) An insulator
(3) A super-conductor             

(4) A semi-conductor

A potential barrier of 0.50 V exists across a P-N junction. If the depletion region is $5.0\times {10}^{-7}$m wide, the intensity of the electric field in this region is 
(1) $1.0\times {10}^6 \mathrm{V}/\mathrm{m}$                     

(2) $1.0\times {10}^5 \mathrm{V}/\mathrm{m}$
(3) $2.0\times {10}^5 \mathrm{V}/\mathrm{m}$                     

(4) $2.0\times {10}^6 \mathrm{V}/\mathrm{m}$

Barrier potential of a P-N junction diode does not depend on 

(1) Temperature               

(2) Forward bias
(3) Doping density             

(4) Diode design

Which is the correct diagram of a half-wave rectifier?

1. 

2. 

3. 

4. 

Zener breakdown takes place if 

(1) Doped impurity is low             

(2) Doped impurity is high
(3) Less impurity in N-part           

(4) Less impurity in P-type