Water is flowing continuously from a tap having an internal diameter `8xx10^-3m`. The water velocity as it leaves the tap is `0.4ms^-1`. The diameter of the water stream at a distance `2xx10^-1m` below the tap is close to:

Options

A. `7.5xx10^(-3)m`
B. `9.6xx10^(-3)m`
C. `3.6xx10^(-3)m`
D. `5.0xx10^(-3)m`

Answer

C

Explanation

From Bernoulli's theorem `rhogh=(1)/(2)rho(v_(2)^(2)-v_(1)^(2))`
`A_(1)v_(1)=A_(2)v_(2),D_(1)^(2)v_(1)=D_(2)^(2)v_(2)` (`D=` pipe diameter)
`V_(2)=sqrt(V_(1)^(2)+2gh)`