Assertion (A): The accuracy of a standard screw gauge is more than the accuracy of a standard vernier caliper.
Reason (R): The least count of standard screw gauge is more than the least count of standard vernier caliper.
A is true but R is false.
The explanation for the correct assertion
We know,
The least count for the screw gauge = 0.01 mm
The least count for the vernier caliper = 0.1 mm
So,
Or, we can say that
So the accuracy of the screw gauge is more than the accuracy of the vernier caliper.
The explanation for the incorrect reason statement
The least count for the screw gauge = 0.01 mm
The least count for the vernier caliper = 0.1 mm
So, the least count of the screw gauge is less than the least count of the vernier caliper.
Hence the correct option is (C) A is true but R is false.