Question

numerical: In an instrument there are 25 divisions on the vernier scale which have length of 24 divisions on the main scale. 1cm on main scale is divided in 20 equal parts. Find the least count.

Answer 1

On main scale cm is divided into 20 equal parts.
Hence 1 M.S.D. = 1/20 cm = 0.05 cm
Now least count = (1/No. of divisions of vernier scale) x M.S.D. = (1/25) x 0.05 cm
= 0.002 cm.