Question

Student $A$ and Student $B$ used two screw gauges of equal pitch and $100$ equal circular divisions to measure the radius of a given wire. The actual value of the radius of the wire is $0.322\, cm$. The absolute value of the difference between the final circular scale readings observed by the students $A$ and $B$ is [Figure shows position of reference '$O$' when jaws of screw gauge are closed]

Answer 1

For $(A)$
Reading $= MSR + CSR +$ Error
$0.322=0.300+ CSR +5 \times LC$
$0.322=0.300+C S R+0.005$
$CSR =0.017$
For $B$
Reading $= MSR + CSR +$ Error
$0.322=0.200+C S R+0.092$
$C S R=0.030$
Difference $=0.030-0.017=0.013\, cm$
Division on circular scale $=\frac{0.013}{0.001}=13$