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

Which one of the following statements is not correct

(1) A diode does not obey Ohm's law

(2) A PN junction diode symbol shows an arrow identifying the direction of current (forward) flow

(3) An ideal diode is an open switch

(4) An ideal diode is an ideal one way conductor

A semiconductor X is made by doping a germanium crystal with arsenic (Z = 33). A second semiconductor Y is made by doping germanium with indium (Z = 49). The two are joined end to end and connected to a battery as shown. Which of the following statements is correct

(1) X is P-type, Y is N-type and the junction is forward biased

(2) X is N-type, Y is P-type and the junction is forward biased

(3) X is P-type, Y is N-type and the junction is reverse biased

(4) X is N-type, Y is P-type and the junction is reverse biased

Which is the wrong statement in following sentences?

A device in which P and N-type semiconductors are used is more useful then a vacuum type because 

(1) Power is not necessary to heat the filament

(2) It is more stable

(3) Very less heat is produced in it

(4) Its efficiency is high due to a high voltage across the junction