Question

In the laboratory, a student measures the thickness of a metal sheet using a screw gauge as shown in the given figure. What is the thickness of the sheet?

• A. 7.81 mm
• B. 7.531 mm
• C. 7.31 mm
• D. 7.831 mm

Answer 1

The correct option is A

7.81 mm

First part of the measurement, P.S.R = 7.5 mm

Head scale division that coincides with the pitch scale axis, H.S.C = 31

Second part of the measurement, H.S.C $\times$ L.C = 31 $\times$ 0.01 mm = 0.31 mm

Measurement with zero error = P.S.R + H.S.C $\times$ L.C = 7.5 + 0.31 = 7.81 mm