The energy gap in case of which of the following is maximum?

Options

A. Germanium
B. Iron
C. Copper
D. Aluminium

Answer

To determine which of the given materials has the maximum energy gap, we need to analyze the properties of each material listed: germanium, iron, copper, and aluminum.

### Step-by-Step Solution:

1. **Understand the Concept of Energy Gap**:
- The energy gap (or band gap) is the energy difference between the valence band (where electrons are present) and the conduction band (where electrons can move freely).
- Materials can be classified as conductors (metals), semiconductors, or insulators based on their energy gaps.

2. **Classify the Materials**:
- **Germanium**: This is a semiconductor with a small energy gap.
- **Iron, Copper, and Aluminum**: These are metals, which typically have overlapping valence and conduction bands, resulting in very small or negligible energy gaps.

3. **Identify Energy Gaps**:
- For **Germanium**, the energy gap is approximately **0.7 eV**.
- For **Metals** (Iron, Copper, Aluminum), the energy gap is effectively **0 eV** because of the overlap of the conduction and valence bands.

4. **Compare the Energy Gaps**:
- Since metals have negligible energy gaps (close to 0 eV) and germanium has an energy gap of 0.7 eV, we can conclude that germanium has the largest energy gap among the options provided.

5. **Conclusion**:
- Therefore, the material with the maximum energy gap among the given options is **Germanium**.

### Final Answer:
The energy gap in case of **Germanium** is maximum among the options provided.