Question

The pitch of an error free screw gauge is 1 mm and there are 100 divisions on the circular scale. While measuring the diameter of a thick wire, the pitch scale reads 1 mm and 63^rd division on the circular scale coincides with the reference line. The diameter of the wire is:

• A. 1.63 cm
• B. 0.163 cm
• C. 0.163 m
• D. 1.63 m

Answer 1

The Correct Option is B

Screw gauge least count (LC): Calculated as Pitch divided by the number of divisions on the circular scale. LC $= \frac{1 \, mm}{100} = 0.01 \, mm$.
Main scale reading (MSR): 1 mm.
Circular scale reading (CSR): 63 divisions.
Final reading: Determined by MSR + (CSR $\times$ LC). Final reading = $1 \, mm + 63(0.01 \, mm) = 1.63 \, mm$, which is equivalent to $0.163 \, cm$.