A soap bubble is blown to a diameter of 7 cm. 36960 erg of work is done in blowing it further. If surface tension of soap solution is 40 dyne $/ \mathrm { cm }$ then the new radius is $\_\_\_\_$ cm. Take $\left( \pi = \frac { 22 } { 7 } \right)$
A soap bubble is blown to a diameter of 7 cm. 36960 erg of work is done in blowing it further. If surface tension of soap solution is 40 dyne $/ \mathrm { cm }$ then the new radius is $\_\_\_\_$ cm. Take $\left( \pi = \frac { 22 } { 7 } \right)$