Arrange the following in the increasing order of their energy gap between their conduction and valence bands:

(A) Si
(B) C (diamond)
(C) Ge
(D) Sn

Choose the correct answer from the options given below:

(D), (C), (A), (B)

The correct answer is Option (1) → (D), (C), (A), (B)

Energy gap increases as we move from materials with metallic character to insulators:

• (D) Sn → very small/zero band gap (behaves like a metal)

• (C) Ge → small band gap (~0.7 eV)

• (A) Si → moderate band gap (~1.1 eV)

• (B) C (diamond) → very large band gap (~5.5 eV, insulator)

Therefore, increasing order: Sn < Ge < Si < Diamond (C)

(D) Sn < (C) Ge < (A) Si < (B) C