Question

A cylinder of height $ 20\, m $ is completely filled with water. The velocity of efflux of water through a hole on the side wall of the cylinder near its bottom is (Take $ g= 10 \,m\, s^{-2} $ )

• A. $ 10\, m\, s^{-1} $
• B. $ 20\, m\, s^{-1} $
• C. $ 25.5 \, m \, s^{-1} $
• D. $ 5 \, m \, s^{-1} $

Answer 1

Answer: (B)

According to Torricelli’s law,
Velocity of efflux, $ v = \sqrt{2gh} $
Here, $ h = 20 \,m $ , $ g = 10 m \,s^{-2} $
$ \therefore v=\sqrt{2\times10\,m\,s^{-2}\times20\,m} $
$ = 20\, m \, s^{-1} $