A disc rotates horizontal at the rate of 100 rpm and M.I. of the disc about the axis of rotation is `1kg m^(2)` . If a blob of molten wax weighing 50 gm drops gently at a distance 20 cm from the axis of rotation of the disc and remains stuck to it, then the increase in moment of inertia of the system will be

Options

A. `2%`
B. `0.2%`
C. `0.02%`
D. `20%`

Answer

B

Explanation

`I_(2)=I_(1)=mr^(2)`
`= 50xx10^(-3)xx20xx20xx10^(-4)`
`= 20xx10^(-4)`
`= (0.20xx10^(-2)xx100)/(100)=0.2%`.