Question

While measuring the length of a rod by vernier calipers the reading on main scale is $6.4\,cm$ and the $8^{th}$ division on the vernier is in line with a main scale division. If the least count of the vernier is $0.01\,cm$ and the zero error is $-0.04\,cm$ , the length (in $cm$ ) of the rod is $\frac{a}{100}$ . Find $a$ .

Answer 1

Length of the rod $=$ observed reading $-$ zero error
$=$ (Main scale division $+$ Vernier scale division $\times L.C.$ ) $-$ Zero error
$=\left(6 . 4 + 8 \times 0 . 01\right)-\left(- 0 . 04\right)$
$=6.4+0.08+0.04=6.52\,cm$