Match List-I with List-II
| List-I | List-II | ||
| Materials | Band gap energy | ||
| (A) | Germanium semiconductor | (I) | 1.1 eV |
| (B) | Silicon semiconductor | (II) | ~ 0 eV |
| (C) | Insulator | (III) | 0.72 eV |
| (D) | Metal | (IV) | > 3.0 eV |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A) - (III), (B) - (I), (C) - (IV), (D) - (II)
The band gap \( E_g \) between the valence and conduction bands decides how easily electrons can be excited into conduction.
(A) Germanium semiconductor — this matches (III) 0.72 eV. Germanium has a smaller gap than silicon, which is why it conducts more at room temperature.
(B) Silicon semiconductor — this matches (I) 1.1 eV.
(C) Insulator — this matches (IV) > 3.0 eV. The gap is too large for thermal energy (about 0.025 eV at room temperature) to lift electrons across.
(D) Metal — this matches (II) ~ 0 eV. In a metal the bands overlap or the conduction band is partly filled, so there is effectively no gap.
NCERT (2026-27):
Extrinsic Semiconductor – “… This is in contrast to the energy required to jump the forbidden band (about 0.72 eV for germanium and about 1.1 eV for silicon) at room temperature in the intrinsic semiconductor.”
Summary – “… 11. For insulators Eg > 3 eV, for semiconductors Eg is 0.2 eV to 3 eV, while for metals Eg ≈ 0.”