I am a verneir Calliper. I have a task to measure the length of a pencil as shown in the figure.
The least count of my Vernier scale is `0.05` times the value of one division of main -scale.

My Vernier Scale has `n`-divisions and coincides with `(n-4)` divisions of main side. While measuring the length of pencil,the `n/5th` division of Verier-Scale exactly coincide the main scale.
Now choose the correct option (s)

Options

A. The value of `n` is 40
B. The least count of Vernier scale is `0.005cm`
C. The length of Pencil is `8.44` cm
D. The length of Pencil is `8.48` cm

Answer

B, D

Explanation

L.C. `=(1)/(20) xx0.1=0.005` cm
Let `1V.S.D.=x`
`implies1/20=1-ximpliesx-=0.95mm`
`(nk-4)xx1=nxx0.95`
`impliesn=80`
Length of pencil `=8.4+0.005xx(80/5)=8.48`cm