The main scale of a vernier callipers reads `10 mm` in `10` divisions. Ten divisions of vernier scale coincide with nine divisions of the main scale. When the two jaws of the callipers touch each other, the fifth division of the vernier coincides with `9` main scale divisions and zero of the vernier is to the right of zero of main scale, when a cylinder is tighty placed between the two jaws, the zero of the vernier scale lies slighty to the left of `3.2 cm` and the fourth vernier division coincides with a main scale division. Find diameter of the cylinder.

Answer

A, C

Explanation

`LC = ("Smallest division on main scale")/("Number of divisions on vernier scale")`
`=(1mm)/(10)=0.1mm =0.01cm`
Positive zero error = `N +x(LC)`
=`0 + 5 xx 0.01`
=`0.05 cm`
Diameter =`3.2 +4 xx 0.01 = 3.24 cm`
Actual diameter =`3.24 -0.05 =3.19 cm` .