169. When a voltage is applied to an intrinsic semiconductor that is at room temperature
A. electrons move to the positive terminal and holes move to the negative terminal
B. holes move to the positive terminal and electrons move the the negative terminal
C. both holes and electrons move to the positive terminal.
D. both holes and electrons move to the negative terminal.
170. When the temperature of an intrinsic semiconductor is increased
A. resistance of the semiconductor increases
B. the heat decreased the energy of the atoms.
C. holes are created in the conduction band
D. the energy of the atoms is increased.
171. A hole is the vacancy created when
A. an electron moves from the conduction band to the valence band.
B. an atomic core moves.
C. an electron breaks its covalent bond.
D. a free electron is made to move by an applied voltage.
172. Movement of a hole is brought about by
A. the vacancy being filled by a free electron.
B. the vacancy being filled by a valence electron from a neighbouring atom.
C. the movement of the atomic cores
D. the atomic core changing from a + 4 to a + 5 charge.
173. If a small amount of arsenic is added to germanium number of
A. holes is increased
B. free electrons is increased.
C. holes and the number of free electrons are increased.
D. holes and the number of free electrons are decreased.
174. If a small amount of antimony is added to germanium
A. the resistanceis increased.
B. the germanium will bea p-type semiconductor
C. is greater in germanium than in silicon.
D. is same in germainum and silicon.
175. n-type impurities
A. create excess holes.
B. can be added to germanium but not to silicon.
C. are called donor impurities.
D. must have only three valence electrons.
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