The energy band gap is maximum in

The correct answer is Option (4) → insulators

The energy band gap is the energy gap between the top of the valence band and the bottom of the conduction band. It decides how easily electrons can be raised into the conduction band.

    \( \text{Metals: bands overlap, } E_g = 0 \)
    \( \text{Semiconductors: } E_g \lt 3\,\mathrm{eV} \text{ (Si about 1.1 eV, Ge about 0.7 eV)} \)
    \( \text{Insulators: } E_g \gt 3\,\mathrm{eV} \text{ (diamond about 5.4 eV)} \)

Insulators have the largest band gap, so almost no electrons reach the conduction band even at room temperature.

Note: A similar question was also asked in CUET (UG) 2023 on 15-06-2023 (Slot 2).

NCERT (2026-27):
Classification of Metals, Conductors and Semiconductors – “… The gap between the top of the valence band and bottom of the conduction band is called the energy band gap (Energy gap \( E_g \)). It may be large, small, or zero, depending upon the material.”

Classification of Metals, Conductors and Semiconductors – “… Case II: In this case, …, a large band gap \( E_g \) exists ( \( E_g \gt 3\ \mathrm{eV} \) ). There are no electrons in the conduction band, and therefore no electrical conduction is possible. … This is the case of insulators.”