The resistance of a semiconductor material (germainum or silicon) `"_________"` with rise in temperature.

Options

A. increase
B. decreases
C. remain the same
D. first increases then decreases

Answer

To solve the question regarding the behavior of resistance in semiconductor materials like germanium or silicon with a rise in temperature, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Relationship**: The resistance \( R \) of a material is related to temperature. For semiconductors, this relationship can be expressed by the formula:
\[ R = R_0 \times (1 + \alpha \times (T - T_0)) \]
where:
- \( R \) is the final resistance,
- \( R_0 \) is the initial resistance,
- \( \alpha \) is the temperature coefficient of resistance,
- \( T \) is the final temperature,
- \( T_0 \) is the initial temperature.

2. **Identify the Type of Material**: Recognize that germanium and silicon are semiconductors. Unlike metals, the resistance of semiconductors decreases with an increase in temperature.

3. **Analyze the Temperature Coefficient**: For semiconductors, the temperature coefficient \( \alpha \) is negative. This means that as the temperature \( T \) increases, the term \( \alpha \times (T - T_0) \) becomes less positive (or more negative), leading to a decrease in resistance \( R \).

4. **Conclusion**: As the temperature rises, the resistance of semiconductor materials like germanium or silicon decreases. Therefore, the correct answer to the question is that the resistance "decreases" with a rise in temperature.

### Final Answer:
The resistance of a semiconductor material (germanium or silicon) **decreases** with rise in temperature.

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