Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

1. Electrons move from lower energy level to higher energy level in the conduction band.

3. Holes in the valence band move from higher energy level to lower energy level.

Solution:
As we apply electric field is applied across a semiconductor, the electrons in the conduction band acquire energy and get accelerated. They travel from lower energy level to higher energy level. While the holes in valence band travel from higher energy level to lower energy level, where they will be having more energy.