Answer= \(0.703\times 10{-3} J \ \ \ or \ \ \ 7.038\times 10^{-4} J\)
Explaination::
Given:: Radius of the bubble = 2 cm or 0.02 m
Surface tension = 0.07 N/m
Solution::
Initial surface area = 0
Final surface area = \(2\times4 \pi r^2\)
increase in surface area = \(2\times 4\pi r^2\)
Work done = Surface tension x increase in surface area
= 0.07 x \(2\times 4\pi r^2\)
=\(0.07\times 8 \times 3.142 \times (0.02)^2\)
=\(7.038\times 10^{-4}\) J
or
=\(0.703 \times 10^{-3} J\)