A small steel ball of radius r is allowed to fall under gravity through a column of a viscous liquid of coefficient of viscosity `eta`. After some time the velocity of the ball attains a constant value known as terminal velocity `upsilon_T`. The terminal velocity depends on (i) the mass of the ball m (ii) `eta`, (iii) r and (iv) acceleration due to gravity g . Which of the following relations is dimensionally correct?

Options

A. `V=(Kmg)/(etar)`
B. `V=(Kmgr)/(eta)`
C. `V=(Km g eta)/(r)`
D. `V=(Kreta)/(mg)`

Answer

A