148. Any voltage that is connected across a P-N junction is called ____ voltage.
A. breakdown
B. barrier
C. bias
D. reverse

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149. The area within a semiconductor diode where no mobile current carriers exist when it is formed is called ___ region
A. depletion
B. saturation
C. potential barrier
D. space charge

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150. The depletion region of a semiconductor diode is due to
A. reverse biasing
B. forward biasing
C. crystal doping
D. migration of mobile charge carriers.

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151. If an intrinsic semiconductor is doped with a very small amount of boron, then in the extinsic semiconductor so formed, the number of electrons and holes will,
A. decrease
B. increase and decrease respectively
C. increase
D. decrease and increase respectively

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152. Two initially identical samples A and B of pure germanium and doped with donors to concentrations of 1 x 10" and 3 x 10" repectively. If the hole concentration in A is 9 x 1012, then the hole concentration in B at the same temperature will be
A. (3 x 1012) m-3
B. (7 x 1012) M-3
C. (11 X 1012) M-3
D. (27 x 1012) m-3

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153. Hall effect is observed in a specimen when it (metal or a semiconductor) is carrying current and is placed in a magnetic field. The resultant electric field inside the specimen will be in
A. a direction normal to both current and magnetic field
B. the direction of curren
C. a direction antiparallel to the magnetic field
D. an arbitrary direction depending upon the conductivity of the specimen

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154.  For a silicon diode, the value of the forwardbias voltage typically
A. must be greater than 0.3 V
B. must be greater the 0.7 V
C. depend on the width of the depletion region
D. depend on the concentration of majority carriers

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