99. Movement of charge carriers from an area of high carrier concentration to an area of low carrier concentration is called
A. drift
B. diffusion
C. recombination
D. gradient

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100. Change of carrier concentration along the length of a semiconductor is called
A. mobility
B. diffusion
C. concetration gradient
D. drift

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101. When a free electron is recaptured by a hole, the process is called
A. recombination
B. diffusion
C. drift
D. restoration

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102. In a semiconductor, movement of charge carriers under influence of an electric field is called
A. diffusion
B. drift
C. mobility
D. conductivity

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103. Imperfections in the crystal structure result in
A. increased conductivity
B. decreased conductivity
C. increased mobility
D. decreased mobility

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104. In pure silicon, major part of the drift current is due to free electrons because
A. there are more free electrons than holes
B. free electrons are in the valence band
C. mobility of electrons is greater than the mobility of holes
D. diffusion constant of electrons is greater then that of holes

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105. At room temperature intrinsic carrier concentration is higher in germanium than in silicon because
A. carrier mobilities are higher Ge than in Si
B. energy gap in Ge is smaller than that in Si
C. atomic number ofGe is larger than in Si
D. atomic weight of Ge is larger than in Si

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