<p>A soap bubble is blown to a diameter of&nbsp; 7cm. 36960 erg&nbsp; of work is done in blowing it further. If surface tension of soap solution is 40 dyne/&nbsp;then the new radius is_____cm. Take&nbsp;<span class="equation">\((\pi = \frac{22}{7})\)</span>​​​​​​​</p>