An isolated and charged spherical soap bubble has a radius ‘ r ‘ and the pressure inside is atmospheric. If ‘ T ‘ is the surface tension of soap solution, then charge on drop is:

Options

A. `2sqrt((2rT)/(epsilon_(0)))`
B. `8pirsqrt(2rT epsilon_(0))`
C. `8pirsqrt(rT epsilon_(0))`
D. `8pirsqrt((2rT)/(epsilon_(0)))`

Answer

B

Explanation

Inside pressure must be `(4T)/T` greater than outside pressure in bubble. This excess pressure is provided by change on bubble.
`(4T)/r=(sigma^(2))/(2 epsilon_(0))`
`(4T)/r=(Q^(2))/(16pi^(2)r^(4)xx2epsilon_(0))....[sigma=Q/(4pir^(2))]`
`Q=8pirsqrt(2 rTepsilon_(0))`