When two soap bubbles of radii a and b ( b > a ) coalesce, the radius of curvature of common surface is:

Open MARKS Web Download App

Search any question & find its solution

Question: Answered & Verified by Expert

When two soap bubbles of radii

a

and

b

(b > a)

coalesce, the radius of curvature of common surface is:

PhysicsMechanical Properties of FluidsJEE MainJEE Main 2021 (17 Mar Shift 1)

Options:

A $\frac{a b}{b - a}$
B $\frac{a + b}{a b}$
C $\frac{b - a}{a b}$
D $\frac{a b}{a + b}$

Solution:

2127 Upvotes Verified Answer

The correct answer is:

\frac{a b}{b - a}

Excess pressure at common surface is given by

$P_{e x} = 4 T (\frac{1}{a} - \frac{1}{b}) = \frac{4 T}{r}$

$∴ \frac{1}{r} = \frac{1}{a} - \frac{1}{b}$

$r = \frac{a b}{b - a}$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.

Use on iOS or Desktop Download from Google Play