Units and Measurements

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the correct answer from the options given below :

1. Both (A) and (R) are correct and (R) is the correct explanation of (A)
2. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
3. (A) is true but (R) is false
4. (A) is false but (R) is true

Answer

(2) Both (A) and (R) are correct but (R) is not the correct explanation of (A)

Solution

Positive zero error: with the jaws closed, the vernier zero lies to the right of the main-scale zero, so the calliper already reads +e.

Observed reading = true reading + e (true reading = observed - zero error)

Reading taken is more than the actual reading (A) is true.

(R): zero error does arise from a manufacturing defect or rough handling (R) is true.

(R) only gives the cause of zero error, not why the reading becomes larger (R) does not explain (A).

Answer: (2)