Precision in measurement depends on

Options

A. Zero error
B. Parallax
C. Least count of instrument
D. Calibration of instrument

Answer

To determine what precision in measurement depends on, let's analyze the options provided:

1. **Zero Error**: This refers to the error that occurs when a measuring instrument does not start from zero. While zero error can affect the accuracy of a measurement, it does not directly relate to the precision of the instrument.

2. **Parallax**: Parallax error occurs when the measurement is read from an angle rather than directly in front of the scale. This can introduce inaccuracies but is also not a direct measure of precision.

3. **Least Count of an Instrument**: The least count is the smallest value that can be measured by the instrument. It directly affects the precision of the measurements because a smaller least count allows for more precise measurements.

4. **Calibration of the Instrument**: Calibration ensures that the instrument provides accurate measurements. While important for accuracy, it does not directly influence the precision of the measurements.

Based on this analysis, the precision in measurement primarily depends on the least count of the instrument. The least count determines how finely the instrument can measure, which is crucial for precision.

### Final Answer:
Precision in measurement depends on the **least count of the instrument** (Option C).

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