Question

The amount of work done in blowing up a soaps bubble of radius 2cm is (given surface tension of soap solution =4 into 10 raise to poer minus 2 N/m)

Answer 1

The amount of work done in blowing up a soap bubble of radius 2cm is (given surface tension of soap solution =4 into 10 raise to power minus 2 N/m)

The work done in blowing up a soap bubble equals surface energy of bubble:

$$A = E _ {S} = \gamma_ {s} S$$

where $\gamma_{s}$ - surface tension, $S = 4\pi r^{2}$ - area of the bubble, $r$ - radius of the bubble

Therefore:

$$A = 4 \pi r ^ {2} \gamma_ {s} = 4 * 3.14 * (0.02 \, m) ^ {2} * 4 * 10 ^ {- 2} \frac {N}{m} = 2 * 10 ^ {- 4} J$$

Answer: $2 * 10^{-4} J$