In semiconductors at a room tempreture

Options

A. the valence band is partially empty and the conductor band is partially filled
B. the valence band is completely filled and the conduction band is partially filled
C. the valence band is completely filled
D. the conduction band is completely empty

Answer

**Step-by-Step Solution:**

1. **Understanding Energy Bands**: In solids, electrons occupy energy levels that are grouped into bands. The two most important bands are the valence band and the conduction band. The valence band is the highest range of electron energies in which electrons are normally present at absolute zero temperature, while the conduction band is the range of electron energies higher than the valence band where electrons can move freely and conduct electricity.

2. **Behavior of Electrons in Different Materials**:
- **Conductors**: In conductors, both the valence band and conduction band overlap, allowing electrons to move freely, resulting in high conductivity.
- **Insulators**: In insulators, the valence band is fully filled and the conduction band is empty, leading to very low conductivity as electrons cannot jump to the conduction band.
- **Semiconductors**: In semiconductors, the valence band is partially filled, and the conduction band is partially filled at room temperature. This allows some electrons to jump from the valence band to the conduction band, enabling conductivity.

3. **Room Temperature Behavior of Semiconductors**: At room temperature, thermal energy allows some electrons to gain enough energy to jump from the valence band to the conduction band. This results in:
- The valence band being partially filled (as some electrons have moved to the conduction band).
- The conduction band being partially filled (as it now contains some electrons that have jumped from the valence band).

4. **Conclusion**: Therefore, at room temperature, in semiconductors, the valence band is partially empty and the conduction band is partially filled.

**Final Answer**: The correct statement is that in semiconductors at room temperature, the valence band is partially empty and the conduction band is partially filled.

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