6. A liquid is coming out from a vertical tube. The relation between the weight of the drop W, surface tension of the liquid T and radius of the tube r is given by, if the angle of contact is zero
(a) w= πr2T
(b) w= 2πrT
(c)w= 2πr2T
(d) w= (3/4)πr3 T
Ans. b
(4)