Question

A soap bubble is being blown on a tube of radius $1cm$. The surface tension of the soap solution is $0.05N/m$ and the bubble makes an angle of ${60}^o$ with the tube as shown. The excess of pressure over the atmospheric pressure in the tube is :

• A. $5Pa$
• B. $1Pa$
• C. $10Pa$
• D. $20Pa$

Answer 1

The correct option is C $10Pa$

We know

Excess pressure $=\frac{2^{2}T}{r}$

$E.P=\frac{2^{2}T}{R}\sin {30}^o$

$E.P.=2\times 2\times \frac{0.05\times 1/2}{0.01}$

$E.P=2\times 5N/m^2$ or $2\times 5Pa=10Pa$

Option $-C$ is correct