The forbidden energy gap for Si is

The correct answer is Option (1) → 1.1 eV

The forbidden energy gap \( E_g \) is the gap between the top of the valence band and the bottom of the conduction band. It is a fixed property of the material, and for silicon at room temperature it is about 1.1 eV.

NCERT (2026-27):
Extrinsic Semiconductor – “… The difference in the resistivity of C, Si and Ge depends upon the energy gap between their conduction and valence bands. For C (diamond), Si and Ge, the energy gaps are 5.4 eV, 1.1 eV and 0.7 eV, respectively.”