When liquid medicine of density is to be put in the eye, it is done with the help of a dropper. As the bulb on the top of the dropper is pressed, a drop forms at the opening of the dropper. We wish to estimate the size of the drop. We first assume that the drop formed at the opening is spherical because that requires a minimum increases in its surface energy. to determine the size, we calculated the net vertical force due to the surface tension T when the radius of the drop is R. when this force becomes smaller than the weight of the drop, the drop gets detched from the dropper.
After the drop detaches, its surface energy is