Question

Why 2T/R is written in total pressure when air bubble of radius R is present inside depth h

Answer 1

Answer: Number of free surfaces is only 1.

Explanation: It depends.

Below a depth of h, the pressure is

P= P° + pgh

(p is density of liquid)

But inside the bubble, there is an excess pressure of 2T/R.

Now why this excess pressure?

For that just remember simply that any concave surface/meniscus would have an excess pressure of 2T/R times the no. Of free surfaces.

Now how many free surfaces are there?

Only one. Because one free surface is inside the bubble which is free and the other surface is 'in contact with the liquid's! so it is not free.

That's why we write 2T/R.

(PS: I could've told you the answer in a line but I thought it would be better to tell you the background as well.Bye.)