Which of the following is the correct ascending order of accuracy?

1. Metre rule, vernier callipers, screw gauge
2. Vernier callipers, metre rule, screw gauge
3. Screw gauge, vernier callipers, metre rule
4. None of the above.

Metre rule, vernier callipers, screw gauge

Reason — The least count of each is :

Meter rule = 0.1 cm
Vernier callipers = 0.01 cm
Screw gauge = 0.001 cm

Hence, the ascending order of accuracy is as follows:

Metre rule, vernier callipers, screw gauge