Radius of Curvature at Soap Bubble Contact Point

[vkash]

Two soap bubbles of radius r and R are in touch find the radius of curvature of their point of contact?
(Both bubbles are touching each other with their external surfaces)

I have no idea about this question. can you please try to help>

 

[Dadface]

What do you know about surface tension?

 

[vkash]

What do you know about surface tension?

No info about surface tension. even answer is in terms r and R.
If you think it can't be done without data related to surface tension then assume that to be S.
answer in book may be wrong...

 

[Dadface]

So do you know the answer?

 

[vkash]

So do you know the answer?

yeah;
It's answer is given in book. But book doesn't provide procedure.

 

[Dadface]

Surface tension does come into it but in this problem it cancels out.Have you studied surface tension?

 

[vkash]

Surface tension does come into it but in this problem it cancels out.Have you studied surface tension?

yes. (I have read surface tension,angle of contact, capillarity, pressure inside a soap and liquid bubble,change in energy when surface expand or collapse).
How do you approach to this question?

 

[Dadface]

Good,so you should know that the pressure inside a bubble is greater than the pressure outside.Now apply that pressure difference formula to the bubbles when they are in contact.There are three radii of relevance r,R and the common radius over their area of contact.

 

[vkash]

Good,so you should know that the pressure inside a bubble is greater than the pressure outside.Now apply that pressure difference formula to the bubbles when they are in contact.There are three radii of relevance r,R and the common radius over their area of contact.

Wow!
great;
i have got the answer.
thanks for helping me.

 

[aakashsotta]

Wow!
great;
i have got the answer.
thanks for helping me.

if u have understood pls help me too i haven't understand nythin abt the common radii