When a tap is closed, the manometer attached to the pipe reads `3.5xx10^(5)Nm^(-2)`. When the tap is opened, the reading of manometer falls to `3.0xx10^(5)Nm^(-2)`. The velocity of water in the pipe is

Options

A. `100m//s`
B. `10m//s`
C. `1 m//s`
D. `10sqrt(10)m//s`

Answer

B

Explanation

Bernoulli's therorem for unit mass of liquid
`(P)/(rho) + 1/2 v^(2) = consta nt`
As the liquid starts flowing , it pressure energy decreases
`1/2v^(2)=(P_(1)-P_(2))/(rho) implies 1/2 v^(2)=(3.5xx10^(5)-3xx10^(5))/(10^3)`
`implies v^(2) = (2xx0.5xx10^(5))/(10^3) implies v^(2) = 100implies 10m//s`.