The specific resistance of a conductor increases with:

Options

A. 1. Increase in temperature
B. 2. Increase in cross section area
C. 3. Increase in cross section and decrease in length
D. 4. Decrease in cross section area

Explanation

To solve the question regarding the increase of specific resistance of a conductor, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Specific Resistance**:
- Specific resistance (or resistivity) is a property of the material that quantifies how strongly it resists the flow of electric current. It is denoted by the symbol ρ (rho).

2. **Identifying Factors Affecting Specific Resistance**:
- Specific resistance is influenced by various factors, but it is essential to note that it is primarily a property of the material itself. It does not change with the physical dimensions of the conductor (length or cross-sectional area).

3. **Evaluating the Options**:
- The question asks what specific resistance increases with. The common factors to consider include:
- Length of the conductor
- Cross-sectional area
- Temperature
- Since specific resistance is a material property, it does not change with length or cross-sectional area.

4. **Temperature's Effect on Specific Resistance**:
- The relationship between specific resistance and temperature can be expressed mathematically. For conductors, the resistivity increases with temperature. The equation is given by:
\[ \rho = \rho_0 (1 + \alpha \Delta T) \]
where:
- \( \rho_0 \) is the resistivity at a reference temperature (often 0°C or 25°C),
- \( \alpha \) is the temperature coefficient of resistivity (positive for conductors),
- \( \Delta T \) is the change in temperature from the reference.

5. **Conclusion**:
- From the above analysis, we conclude that the specific resistance of a conductor increases with temperature due to the positive temperature coefficient of resistivity.

### Final Answer:
The specific resistance of a conductor increases with **temperature**.