Question

The class of materials having the largest band gap in the following is

• A. Metals
• B. Semi-metals
• C. Semiconductors
• D. Insulators

Hint:

Band gap order is: \[ \text{Metals} < \text{Semi-metals} < \text{Semiconductors} < \text{Insulators}. \] Larger band gap means lower electrical conductivity.

Answer 1

The Correct Option is D

Step 1: Define band gap and its role.
Band gap separates valence and conduction bands; larger gap means fewer electrons can jump across.

Step 2: Compare material classes.
Metals: E_g ≈ 0 (overlapping bands). Semiconductors: E_g ≈ 0.1–3 eV. Insulators: E_g>3 eV, typically 5–10 eV.

Step 3: Identify largest gap.
Insulators possess the largest band gap.

Step 4: Final Answer:
Insulators (option 4).