A particle of mass 10g is kept on the surface of a uniform sphere of mass 100 kg and radius 10 cm. Find the work to be done against the gravitational force between them, to take the particle far away from the sphere (you may take `G=6.67xx10^(-11)Nm^(2)//kg^(2))`

Options

A. `13.34xx10^(-10)J`
B. `3.33xx10^(-10)J`
C. `6.67xx10^(-9)J`
D. `6.67xx10^(-10)J`

Answer

D

Explanation

Work done `=U_(f)-U_(i)=U_(f)=0-(-0)`
`U_(i)=(GM_(1)m_(2))/(R)=(6.67xx10^(-4)xx100xx10xx10^(-1))/(10xx10^(2))`
`=(6.67xx10^(-11)xx100xx10xx10^(-3))/(10xx10^(-2))=6.67xx10^(-10)`