In a horizontal pipe of non-uniform cross section, water flows with a velocity of `1ms^(-1)` at a point where the diameter of the pipe is 20 cm. The velocity of water `(ms^(-1))` at a point where the diameter of the pipe 10 cm is:

Options

A. 0.0025 m/s
B. 0.25 m/s
C. 0.025 m
D. 0.5 m/s

Answer

B

Explanation

`v_(1)=1m`
`d_(1)=20xx10^(-2)m`
`v_(2)=?`
`d_(2)=10xx10^(-2)m`
`(5)/(4)d_(1)^(2)v_(1)=(5)/(4)d_(2)^(2)v_(2)`
`d_(1)^(2)v_(1)=d_(2)^(2)v_(2)`
`(v_1)/(v_2)=(d_(2)^(2))/(d_(1)^(2))`
`(1)/(v_2)=((20xx10^(-2))^(2))/((10xx10^(-2))^(2))`
`(1)/(v_2)=4`
`v_(2)=(1)/(4)m//s`
`=.25m//s`