The resistance of a semiconductor on heating

remains constant
decreases
increases
None of the above

The correct answer is (b). The resistance of a semiconductor decreases on heating. This is because the increase in temperature causes the electrons to move more freely, which in turn decreases the resistance.

Option (a) is incorrect because the resistance of a semiconductor does not remain constant on heating. Option (c) is incorrect because the resistance of a semiconductor decreases on heating, not increases. Option (d) is incorrect because the resistance of a semiconductor does change on heating.