In the searle's experiment, after every step of loading, why should we wait for two minutes before taking the reading?( More than one options may be correct).

Options

A. (a)So that the wire can have its desired change in length.
B. (b)So that the wire can attain room temperature.
C. (c)So that vertical oscillations can get subsided.
D. (d)So that the wire has no change in its radius.

Answer

To answer the question regarding why we should wait for two minutes before taking readings in Searle's experiment, we can analyze the options provided step by step.

### Step-by-Step Solution:

1. **Understanding the Experiment**: Searle's experiment involves measuring the elongation of a wire when weights are applied. The wire is subjected to tensile stress, and we need to ensure that the readings taken are accurate.

2. **Option A - Desired Change in Length**:
- When a weight is applied to the wire, it takes some time for the wire to stretch to its new length due to the material's properties.
- **Conclusion**: Waiting allows the wire to reach its desired elongation. This statement is correct.

3. **Option B - Attaining Room Temperature**:
- The application of weight can cause the wire to heat up due to internal friction and deformation.
- By waiting, the wire can cool down to room temperature, ensuring that temperature effects on elongation are minimized.
- **Conclusion**: This statement is also correct.

4. **Option C - Subsidizing Vertical Oscillations**:
- When weights are added, the wire may vibrate or oscillate due to the sudden application of force.
- Waiting allows these oscillations to dampen, providing a stable reading.
- **Conclusion**: This statement is correct as well.

5. **Option D - No Change in Radius**:
- When the wire is stretched, its radius does change due to the conservation of volume (assuming incompressibility).
- The statement implies that waiting will prevent any change in radius, which is incorrect since stretching will inherently affect the radius.
- **Conclusion**: This statement is incorrect.

### Final Conclusion:
The correct answers are options A, B, and C. We wait for two minutes to ensure the wire has its desired change in length, to allow it to attain room temperature, and to let any vertical oscillations subside.