Question

If more air is pushed in a soap bubble, the pressure in it

• A. decreases
• B. increases
• C. remains same
• D. becomes zero

Answer 1

The correct option is A decreases

We know that pressure inside soap bubble is given by
$P_2=P_1+\frac{4T}{R}$, where $T$ is surface tension and $P_1$ is outside pressure.


$\Rightarrow P_2\propto \frac{1}{R}$
As more air is pushed into a soap bubble, its volume will increase. This increases the radius of the soap bubble.
Therefore, pressure inside it will decrease.