Match List-I with List-II for the band gap energy for different materials
| List-I | List-II |
| Substances | Band gap Energy |
| (A) Germanium | (I) 1.1 eV |
| (B) Silicon | (II) 0.7 eV |
| (C) Insulator | (III) Zero |
| (D) Metal | (IV) 5 eV |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A) - (II), (B) - (I), (C) - (IV), (D) - (III)
The energy gap \( E_g \) between the valence band and the conduction band separates the three classes of solid: it is zero for a metal, small for a semiconductor and large for an insulator.
(A) Germanium — this matches (II) 0.7 eV. Germanium is a semiconductor with a gap of about 0.7 eV.
(B) Silicon — this matches (I) 1.1 eV. Silicon has a slightly larger gap of about 1.1 eV.
(C) Insulator — this matches (IV) 5 eV. An insulator has a large gap (more than about 3 eV), so electrons cannot be excited across it at room temperature.
(D) Metal — this matches (III) Zero. In a metal the conduction and valence bands overlap, so there is no gap.
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. Sn also is a group IV element but it is a metal because the energy gap in its case is 0 eV.”