question_answer

Water is flowing through a horizontal tube having cross-sectional areas of its two ends being A and A' such that the ratio A/A' is 5. If the pressure difference of water between the two ends is \[3\times {{10}^{5}}N{{m}^{-2}},\] the velocity of water with which it enters the tube will be (neglect gravity effects)                                [JEE ONLINE 12-05-2012]

A)  \[5\,m\,{{s}^{-1}}\]    

B)       \[10\,m\,{{s}^{-1}}\]

C)  \[25\,m\,{{s}^{-1}}\]  

D)       \[50\sqrt{10}\,m\,{{s}^{-1}}\]

Correct Answer: A

Solution :

[a] According to Bernoulli's theorem

(i)

From question,

According to equation of continuity

or,

From equation (i)

or