Semiconductor Electronics Materials Devices and Simple Circuits - Result Question 27
27. Choose the only false statement from the following
[2005]
(a) In conductors, the valence and conduction bands may overlap
(b) Substances with energy gap of the order of $10 eV$ are insulators
(c) The resistivity of a semiconductor increases with increase in temperature
(d) The conductivity of a semiconductor increases with increase in temperature
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Answer:
Correct Answer: 27. (c)
Solution:
- (c) (a) is true as in case of conductors either the conduction & valence band overlap or conduction band is partially filled.
(b) is true as insulators have energy gap of the order of 5 to $10 eV$.
(c) is false as resistivity (opposite of conductivity) decreases with increase in temperature.
(d) is true as with increase in temperature more and more electrons jump to the conduction band. So, conductivity increases.
