In a vernier callipers, 10 vernier scale divisions coincide with 9MSD each of value 1mm. While measuring length of a cylinder using this calliper, main scale reading is 5.1 cm and 7th vernier division coincides with any main scale division. Whenm diameter of cylinder is measured, main scale reading is 1.7 cm and 3rd vernier division coincides with any main scale division. Calculate curved surface area of the cylinder with correct number of significant figures.

Answer

`28.1 cm^2`

Explanation

V.C = 1 MSD -1 VSD `= (1-(9)/(10))MSD`
`=(1)/(10)MSD = (1)/(10)mm =0.1mm`
`=0.01cm`
`I = (5.1xx7xx0.01)cm =5.17cm`
`D = (1.7+ 3xx0.01)cm =1.73cm`
curved surface area `=2pi rxx I =pi DI`
`=3.14(1.73)5.17cm^2`
`A = 28.084cm^2`
Rounding off to three significant digits,
`A = 28.1cm^2`