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:

(1) 1.63 cm

(2) 0.163 cm

(3) 0.163 m

(4) 1.63 m

Answer 1

Correct option is : (2) 0.163 cm

Least count of screw gauge \( =\frac{\text { Pitch }}{\text { No. of divisions on circular scale }}\)

\(\Rightarrow\) Least count \(=\frac{1}{100}=0.01 \ \mathrm{mm}\)

Final reading \(=\mathrm{MSR}+\mathrm{CSR} \times\) L.C.

\(=1 \ \mathrm{mm}+(63)(0.01) \ \mathrm{mm} \) 

\(=1.63 \mathrm{~mm}\) 

\( =0.163 \mathrm{~cm}\)