Which of the following measures a small length to a high accuracy: metre rule, vernier callipers, screw gauge ?

Explanation

To determine which instrument measures small lengths with high accuracy among a metre rule, vernier calipers, and a screw gauge, we can follow these steps:

### Step 1: Understand the concept of least count
The least count of an instrument is the smallest measurement that can be accurately read with that instrument. The smaller the least count, the higher the accuracy of the measurement.

### Step 2: Identify the least counts of each instrument
- **Metre Rule**: The least count is 1 mm (0.1 cm).
- **Vernier Calipers**: The least count is 0.1 mm (0.01 cm).
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