Energy band gap is maximum in:

The correct answer is Option (4) → insulator

The energy band gap is the forbidden energy gap between the top of the valence band and the bottom of the conduction band. The larger it is, the harder it is for electrons to reach the conduction band, so the material conducts less.

Option (1) metals — Incorrect. In metals the valence and conduction bands overlap (or the conduction band is partly filled), so there is no forbidden gap at all.

Option (2) semi-conductor — Incorrect. A semiconductor has a small gap, less than about 3 eV (about 1.1 eV for silicon), so some electrons cross it at room temperature.

Option (3) super conductor — Incorrect. A superconductor is a material whose resistance drops to zero below a critical temperature. It is a conducting material, not one with a wide forbidden gap.

Option (4) insulator — Correct. An insulator has a wide gap, more than about 3 eV, so almost no electrons can be raised to the conduction band and it does not conduct.

Note: A similar question was also asked in CUET (UG) 2026 on 31-05-2026 (Slot 2).

NCERT (2026-27):
Classification of Metals, Conductors and Semiconductors – “… Case II: In this case, as shown in Fig. 14.2(b), a large band gap E_g exists (E_g > 3 eV). There are no electrons in the conduction band, and therefore no electrical conduction is possible. … This is the case of insulators.”