Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : In Vernier calliper if positive zero error exists, then while taking measurements, the reading taken will be more than the actual reading.
Reason (R) : The zero error in Vernier Calliper might have happened due to manufacturing defect or due to rough handling.
In the light of the above statements, choose the correct answer from the options given below :

We need to evaluate the Assertion and Reason about Vernier callipers.

Assertion (A): In a Vernier calliper, if positive zero error exists, the reading taken will be more than the actual reading.

This is true. Positive zero error means the zero of the vernier scale is to the right of the zero of the main scale when the jaws are closed. This adds an extra amount to every reading, making measured values larger than actual values. The correction requires subtracting the zero error.

Reason (R): The zero error in a Vernier calliper might have happened due to manufacturing defect or due to rough handling.

This is true. Manufacturing imperfections or damage from rough use can cause the jaws to not align properly at zero.

However, R merely explains the cause of zero error in general, not why positive zero error specifically leads to higher readings. R does not explain the mechanism described in A.

The correct answer is Option 2: Both (A) and (R) are correct but (R) is not the correct explanation of (A).