Semiconductor Electronics Materials Devices and Simple Circuits - Result Question 31

31. In semiconductors, at room temperature [2004]

(a) the conduction band is completely empty

(b) the valence band is partially empty and the conduction band is partially filled

(c) the valence band is completely filled and the conduction band is partially filled

(d) the valence band is completely filled

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Answer:

Correct Answer: 31. (c)

Solution:

  1. (c) In semiconductors, the conduction band is empty and the valence band is completely filled at $0 K$. No electron from valence band can cross over to conduction band at $0 K$. At room temperature some electrons in the valence band jump over to the conduction band due to the small forbidden gap, i.e. $1 eV$.