The top of a water tank is open to air and its water lavel is maintained. It is giving out `0.74 m^(3)` water per minute through a circular opening of 2 cm radius in its wall. The depth of the centre of the opening from the level of water in the tank is close to :

Options

A. 2.9m
B. 9.6m
C. 4.8m
D. 6.0m

Answer

C

Explanation

Volume of water coming out per minute.
`(triangleV)/(trianglet)=0.74"m^(2)/min"`
`=(0.74)/(60)m^(3)//sec ........(i)`
Volume flow rate of water from hole `=(triangleV)/(triangle t)=Av`
`Av=pi xx (0.02)^(2)xx v..........(ii)`
From equations (i) and (ii)
`pi (0.02)^(2)v= (0.74)/(60)m^(3)//sec`
`rArr v=9.81 m//s`
Velocity of efflux, `v=sqrt(2gh)`
`h=v^(2)/(2g)=4.8m`