Fluid Mechanics Viscosity Question 61

Question: Two capillary tubes of same diameter are put vertically one each in two liquids whose relative densities are 0.8 and 0.6 and surface tensions are 60 and 50 dyne/cm respectively Ratio of heights of liquids in the two tubes$ \frac{h_{1}}{h_{2}} $ is [MP PMT 2002]

Options:

A) $ \frac{10}{9} $

B) $ \frac{3}{10} $

C) $ \frac{10}{3} $

D) $ \frac{9}{10} $

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Answer:

Correct Answer: D

Solution:

Ascent formula $ h=\frac{2T\cos \theta }{rdg} $ $ \Rightarrow \frac{h_{1}}{h_{2}}=\frac{T_{1}}{T_{2}}\times \ \frac{d_{2}}{d_{1}} $ ($ r,\ \theta $ and g are constants) $ \Rightarrow \frac{h_{1}}{h_{2}}=\frac{60}{50}\times \frac{0.6}{0.8}=\frac{9}{10} $