1000 drops of a liquid each of diameter 4 mm coalesce to form a single large drop. If surface tension of liquid is 35 "dyn "cm^(-1), calculate the energy evolved by the system in the process.

1000 drops of a liquid each of diameter 4 mm coalesce to form a single

1.	1000 drops of a liquid each of diameter 4 mm coalesce to form a single large drop. If surface tension of liquid is 35 "dyn "cm^(-1), calculate the energy evolved by the system in the process.
Answer» Solution :Number of drops N = 1000 `rArrn^(1//3)=10rArrn^(2//3)=100` Surface TENSION of liquid T = 35 dyne `cm^(-1)` Radius of each small drop r = 2 mm = 0.2 cm Energy evolved in merging `W=4pir^(2)T[n-n^(2//3)]rArrW=4xx22/7xx(2XX10^(-1))^(2)35[1000-100]` `rArrW=(88xx35xx4xx10^(-2))/7[900]` = 15840 ergs. `~~1.58xx10^(-3)J`