[" (1) "2 pi mf],[" Two merucry drops (each of radius 'r') merge to form a bigger drop.The surface energy of the "],[" drop,ifs Tisthe surface tension,is: "],[[" (1) "2^(5/7)pi r^(2)T," (2) "4 pi r^(2)T," (3) "2 pi r^(2)T," (4) "2^(8/3)pi r^(2)T]]