Question

If two soap bubbles of radii r and 2r form a double bubble. Then the radius of curvature of the
interface between the two bubbles will be
(1) r/2
(2) 2r
(3) 3r
(4) 20/3​

Answer 1

Answer:

Let say P

1

and P

2

are the excess pressure on the two sides of the interface then the resultant excess pressure is P

⇒P=P

2

−P

1

⇒

r

4T

=

r

2

4T

−

r

1

4T

⇒

r

1

=

r

2

1

−

r

1

1

⇒

r=

r

1

−r

2

r

1

r

1