question_answer

Two tubes of radii \[{{r}_{1}}\] and \[{{r}_{2}},\] and lengths \[{{I}_{1}}\] and \[{{I}_{2}},\] respectively, are connected in series and a liquid flows through each of them in stream line conditions. \[{{P}_{1}}\] and \[{{P}_{2}}\] are pressure differences across the two tubes. If \[{{P}_{2}}\] is \[4{{P}_{1}}\] and \[{{I}_{2}}\] is \[\frac{{{I}_{1}}}{4},\] then the radius \[{{r}_{2}}\] will be equal to -                                                                             [JEE Online 09-04-2017]

A)  \[4{{r}_{1}}\]             

B)       \[{{r}_{1}}\]

C)  \[2{{r}_{1}}\]             

D)       \[\frac{{{r}_{1}}}{2}\]

Correct Answer: D

Solution :

[d]