The valence band at 0 K is-

Options

A. completely filled
B. completely empty
C. partially filled
D. nothing can be said

Answer

To solve the question regarding the state of the valence band at 0 Kelvin, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Bands in Semiconductors**:
- In semiconductors, there are two primary energy bands: 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 (0 K).

2. **Behavior of Electrons at 0 K**:
- At absolute zero (0 K), thermal energy is minimal. This means that electrons do not have enough energy to jump from the valence band to the conduction band.

3. **Filling of the Valence Band**:
- Since there is no thermal energy available at 0 K, all the electrons in the valence band remain in their respective positions. Thus, the valence band is fully occupied by electrons.

4. **Conclusion**:
- Therefore, at 0 K, the valence band is completely filled with electrons.

5. **Final Answer**:
- The correct answer to the question is that the valence band at 0 K is **completely filled**.