A solide ball of volume V is dropped in a viscous liquid. It experiences a viscous force F. If the solid ball of volume 2V of same material is dropped in the same fluid, then the viscous force acting on it will be

Options

A. ` nF// 2 `
B. `F// 2 `
C. `2F `
D. `2 nF `

Answer

C

Explanation

Viscous force , F = ` 6 pi eta r v `
but ` v prop r ^ 2 `
` therefore F prop V " " ` ( volume )
so, on doubline the volume of the ball, the viscous force is doubled.