Question

Define energy band in solids.

Hint:

In semiconductors and insulators, the energy gap between valence and conduction bands determines their conductivity.

Answer 1

Step 1: In solids, atomic energy levels overlap due to the close proximity of atoms, forming continuous ranges called energy bands. Step 2: The two main types of bands in a solid are the valence band (occupied by electrons) and the conduction band (where free electrons exist). Step 3: The gap between these bands determines the electrical properties of the material. \[ \therefore \text{Energy bands define the allowed energy levels in a solid.} \] \[ \boxed{\text{Energy bands are ranges of electron energy levels in solids.}} \]