Properties Of Solids And Liquids Question 235
Velocity of water in a river is uniform[CBSE PMT 1988]
Options:
2
3
4
D) $ 2\sqrt{2} $
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Answer:
Correct Answer: C
Solution:
$ t=\frac{A}{a}\sqrt{\frac{2}{g}}\left[ \sqrt{H _{1}}-\sqrt{H _{2}} \right] $
Now, $ T _{1}=\frac{A}{a}\sqrt{\frac{2}{g}}\left[ \sqrt{H}-\sqrt{\frac{H}{\eta }} \right] $
and $ T _{2}=\frac{A}{a}\sqrt{\frac{2}{g}}\left[ \sqrt{\frac{H}{\eta }}-\sqrt{0} \right] $ A
According to problem $ T _{1}=T _{2} $ $ \sqrt{H}-\sqrt{\frac{H}{\eta }}=\sqrt{\frac{H}{\eta }}-0 $
therefore $ \sqrt{H}=2\sqrt{\frac{H}{\eta }}\Rightarrow \eta =4 $
BETA
