91. Diffusion current in a diode is caused by
a. chemical energy
b. heat energy
c. voltage
d. crystal formation

92. Depletion region in a pn diode is due to
a. reverse biasing
b. forward biasing
c. an area created by crystal doping
d. an area void of current carriers

93. Depletion region in a pn junction diode consist of
a. mobile donor ions
b. mobile acceptor ions
c. mobile donor and acceptor ions
d. majority carriers

94. The photo electric current in ampere per wat of incident light depend on
a. frequency of incident light
b. intensity of incident light
c. frequency and intensity of incident light
d. frequency wavelength and intensity incident light

95. When a diode is forward biased
a. barrier potential increases
b. barrier potential decreases
c. majority current reduces
d. minority current reduces

96. In a case of photon conductor for germanium when forbidden energy gap is 0.72 eV , the critical wave length for intrinsic excitation will be
a. 1.43 m
b. 1.43 um
c. 1.73 um
d. 1.73 exponent -13 m

97. The work function of a photo surface whose threshold wave length is 12,00 A, will be
a. 0.103 eV
b. 0.673 eV
c. 1.03 eV
d. 1.27 eV

98. A potential difference is developed across a current carrying metal strip when the strip is placed in a transverse magnetic field , The above effect is known as
a. Fermi”s effect
b. Photo electric effect
c. Joule effect
d. Half effect

99. As the temperature of a semi-conductor is reduced to absolute zero
a. all electron become zero
b. all electron cease to move
c. all valence electrons tend to remain in the valence band
d. all valence electrons shift to forbidden gap

100. Which of the following element belong to the same groups of period table as that of Germanium and Silicon
a. Carbon
b. Sulphur
c. Copper
d. Gold