A cylindrical drum, open at the top, contains `30` litres of water. It drains out through a small opening at the bottom. `10` litres of water comes out in time `t_1`, the next `10`litres in a further time `t_1` and the last `10` litres in a further time `t_3` Then,

Options

A. `t_1 = t_2 = t_3`
B. `t_1 gt t_2 gt t_3`
C. `t_1 lt t_2 lt t_3`
D. `t_2 gt t_1 = t_3`

Answer

C

Explanation

Velocity of efflux `v = sqrt(2 gh)`,
`h` : height of liquid
As water drains out, `h` decreases and hence `v` reduces. This results in decrease in rate of drainage.
`t_1 lt t_2 lt t_3`.