Two droplets each radius r of mercury mergeand form a bigger drop . If surface tension of mercury is T.Then what will be the surface energy ?

Two droplets each radius r of mercury mergeand form a bigger drop . If

1.	Two droplets each radius r of mercury mergeand form a bigger drop . If surface tension of mercury is T.Then what will be the surface energy ?
Answer» `2^((5)/(3))pir^(2)T` `4pir^(2)T` `2pir^(2)T` `2^((8)/(3)pir^(2))T` Solution :Radius of small droplet is R and volume is `V_(1)` when TWO droplets are merged and form a bigger drop having radius R and volume is `V_(2)` `thereforeV_(2)=V_(1)xx2` `(4)/(3)piR^(3)=2XX(4)/(3)pir^(3)` `R^(3)=2r^(3)` `R=2^((1)/(3))xxr`...(1) Now , surface enerfy of bigger drop, `E=4piR^(2)T=4pi(2^((2)/(3))*r^(2))T=pixx2^(2)xx2^((2)/(3))xxr^(2)T` `=pixx2^(2+(2)/(3))xxr^(2)T` `thereforeE=2^((8)/(3))pir^(2)T`