JEE PYQ: Mechanical Properties Of Fluids Question 5
Question 5 - 2021 (17 Mar 2021 Shift 2)
Suppose you have taken a dilute solution of oleic acid in such a way that its concentration becomes 0.01 cm$^3$ of oleic acid per cm$^3$ of the solution. Then you make a thin film of this solution (monomolecular) of area 4 cm$^2$ by considering 100 spherical drops of radius $\left(\frac{3}{40\pi}\right)^{1/3} \times 10^{-3}$ cm. Then the thickness of oleic acid layer will be $x \times 10^{-14}$ m. Where $x$ is ______
Show Answer
Answer: 25
Solution
$4t_T = 100 \times \frac{4}{3}\pi r^3$ $= 100 \times \frac{4\pi}{3} \times \frac{3}{40\pi} \times 10^{-9} = 10^{-8}$ cm$^3$ $t_T = 25 \times 10^{-10}$ cm $= 25 \times 10^{-12}$ m $t_0 = 0.01 \times t_T = 25 \times 10^{-14}$ m $x = 25$
BETA
