The zeroth divisions of the vernier and main scales of a standard vernier callipers coincide, then

Options

A. the external jaws are in contact with each other
B. there is some distance between the internal jaws.
C. Both (a) and (b).
D. Neither (a) nor (b).

Explanation

To solve the problem regarding the coincidence of the zeroth divisions of the vernier and main scales of a standard vernier caliper, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Setup**:
- A vernier caliper consists of a main scale and a sliding vernier scale. Each scale has a zeroth division (0 mark).
- When we say that the zeroth divisions of both scales coincide, it means that when the jaws of the caliper are closed (not measuring anything), the 0 mark of the main scale aligns perfectly with the 0 mark of the vernier scale.

2. **Interpreting Coincidence**:
- Coinciding zeroth divisions indicate that there is no gap or separation between the jaws of the caliper when they are closed. This is crucial for accurate measurements.
- If the jaws are perfectly closed and the scales coincide, it means that the caliper is calibrated correctly.

3. **Conclusion**:
- Therefore, if the zeroth divisions of the vernier and main scales coincide, it implies that there is no distance or separation between the internal jaws of the caliper. This is an important condition for accurate measurement.

4. **Final Answer**:
- The correct conclusion is that there is no separation between the jaws of the caliper when the zeroth divisions coincide.