The electrical resistivity of a semiconductor :

Options

A. increases with temperature
B. decreases with temperature
C. increase at low temperature and then decreases
D. does not change with temperature

Answer

### Step-by-Step Solution:

1. **Understanding Resistivity in Semiconductors**:
- Resistivity is a measure of how strongly a material opposes the flow of electric current. In semiconductors, this property is influenced by temperature.

2. **Effect of Temperature on Carrier Concentration**:
- At low temperatures, semiconductors have fewer charge carriers (electrons and holes). As the temperature increases, more electrons gain enough energy to jump from the valence band to the conduction band, thus increasing the number of charge carriers.

3. **Relationship Between Resistivity and Temperature**:
- As the number of charge carriers increases with temperature, the ability of the semiconductor to conduct electricity improves. Therefore, the resistivity decreases with an increase in temperature.

4. **Conclusion**:
- The correct answer to the question is that the electrical resistivity of a semiconductor decreases with an increase in temperature.

### Final Answer:
- The electrical resistivity of a semiconductor **decreases with temperature**.

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