Question

Two soap bubbles of different diameters are blown on the opposite ends of a glass
tube with a valve on it.
What will be the effect on the diameter of smaller soap bubble if the valve is opened?
Justify.​

Answer 1

Answer:

First see the attached photo to visualize the setup.

As per the question, two soap bubbles are blown and connected by a valve (initially closed).

Now, you need to remember the fact that

Smaller radius soap bubble will have a higher excess pressure.

Smaller radius soap bubble will have a higher excess pressure.Whereas the larger soap bubble will have lower excess pressure.

This can be understood with the equation

∆P = 2T/R,

where ∆P is the excess pressure, T is the surface tension, R is the Radius of the soap bubble.

So higher radius indicates lower pressure.

Now when the valve is opened, air will flow from smaller bubble ( due to higher internal pressure) to larger bubble ( due to lower pressure).

So the smaller bubble will become even smaller , while larger bubble will still become larger .

Answer 2

Explanation:

two soap bubbles are blown and connected by a valve (initially closed). Smaller radius soap bubble will have a higher excess pressure. Smaller radius soap bubble will have a higher excess pressure