Two spherical soap bubbles of radii a and b in vacuum coalesce under isothermal condition. The resulting bubbles has a radius given by …..

Options

A. `(a+b)/(2)`
B. `(ab)/(a+b)`
C. `sqrt(a^(2)+b^(2))`
D. a+b

Answer

c

Explanation

Here , the bubbles coalesce in vacuum and there is no change in temperature ,hence its surface energy does not change .This means that the surface area remains unchanged .
Hence ,`4pia^(2)+4pib^(2)=4piR^(2)thereforeR=sqrt(a^(2)+b^(2))`