Q: There is a hole at the side-bottom of a big water tank. The area of the hole is 4mm2. Through it a pipe is connected. The upper surface of water is 5 m above the hole. The rate of flow of water through the pipe is (in m³s-1) (g = 10 ms-2)
(a) 4 × 10-5
(b) 4 × 105
(c) 4 × 10-6
(d) 28 × 10-5
Ans: (a)
Sol:
Velocity of efflux is
$ \displaystyle v = \sqrt{2 g h} $
$ \displaystyle = \sqrt{2 \times 10 \times 5} = 10 m/s $
Rate of flow
$ \displaystyle = A v = 4 \times 10^{-6}\times 10 $
= 4 × 10-5