PN-junction diode works as a insulator, if connected

(1) To A.C.                             

(2) In forward bias
(3) In reverse bias                   

(4) None of these

The PN junction diode is used as

(1) An amplifier                       

(2) A rectifier
(3) An oscillator                       

(4) A modulator

Two PN-junctions can be connected in series by three different methods as shown in the figure. If the potential difference in the junctions is the same, then the correct connections will be 

(a) In the circuit (1) and (2)                    (b) In the circuit (2) and (3)
(c) In the circuit (1) and (3)                    (d) Only in the circuit (1)

On increasing the reverse bias to a large value in a PN-junction diode, current

(1) Increases slowly                 

(2) Remains fixed
(3) Suddenly increases             

(4) Decreases slowly

A semiconductor device is connected in a series circuit with a battery and a resistance. A current is found to pass through the circuit. If the polarity of the battery is reversed, the current drops almost to zero. The device may be

(1) A P-type semiconductor               

(2) An N-type semiconductor
(3) A PN-junction                               

(4) An intrinsic semiconductor

In a junction diode, the holes are due to

(1) Protons                               

(2) Neutrons
(3) Extra electrons                     

(4) Missing of electrons

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

In a p-n junction diode not connected to any circuit:

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