A soap bubble (surface tension = T) is charged to a maximum surface density of charge = $\mathrm{\sigma }$ When it is just going to burst, its radius R is given by

• A

  $\mathrm{R}=\frac{{\mathrm{\sigma }}^2}{8{\mathrm{\epsilon }}_0\mathrm{T}}$

• B

  $\mathrm{R}=8{\mathrm{\epsilon }}_0\frac{\mathrm{T}}{{\mathrm{\sigma }}^2}$

• C

  $\mathrm{R}=\frac{\mathrm{\sigma }}{\sqrt{8{\mathrm{\epsilon }}_0\mathrm{T}}}$

• D

  $\mathrm{R}=\frac{\sqrt{8{\mathrm{\epsilon }}_0\mathrm{T}}}{\mathrm{\sigma }}$