With the rise in temperature, the electrical resistance

The correct answer is Option (3) → increases for a conductor and decreases for a semiconductor

The resistance of a material depends on the number of free charge carriers and on how often they collide.

Option (1) increases for a conductor and a semiconductor — Incorrect. The resistance of a semiconductor does not increase on heating.

Option (2) decreases for a conductor and a semiconductor — Incorrect. The resistance of a conductor does not decrease on heating.

Option (3) increases for a conductor and decreases for a semiconductor — Correct. In a metallic conductor the number of free electrons is almost fixed, but the collisions become more frequent, so the relaxation time falls and the resistance rises. In a semiconductor heating frees many more electrons and holes, and this outweighs the extra collisions, so the resistance falls.

Option (4) decreases for a conductor and increases for a semiconductor — Incorrect. This is the reverse of what happens.

NCERT (2026-27):
Temperature Dependence of Resistivity – “… Unlike metals, the resistivities of semiconductors decrease with increasing temperatures.”

Temperature Dependence of Resistivity – “… In a metal, \( n \) is not dependent on temperature to any appreciable extent and thus the decrease in the value of \( \tau \) with rise in temperature causes \( \rho \) to increase as we have observed. For insulators and semiconductors, however, \( n \) increases with temperature. This increase more than compensates any decrease in \( \tau \) in Eq.(3.23) so that for such materials, \( \rho \) decreases with temperature.”