A sphere of radius R is gently dropped into liquid of viscosity `eta` in a vertical uniform tube. It attains a terminal velocity v. Another sphere of radius 2 R when dropped into the same liquid, will attain its teriminal velocity.

Options

A. v
B. 2v
C. 4v
D. 9v

Answer

C

Explanation

Terminal velocity
`vprop r^2`
`(v')/(v)=((2R)^2)/((R)^2)rArr v'=4v`