64 equally charged water-droplets, each of radius 4 mm, are combined to form a large water-drop. Determine the ratio of the surface densities of charges in the two cases.

Two spheres of radii 4 cm and 8 cm have the same amount of charge. Determine the ratio of their surface densities of charge.

27 drops of water, each of radius 3 mm and having equal charge are combined to form a large drop. Find the ratio of the surface density of charge on the large drop to that on each small drop.

The ratio of the radii of two spheres is 5:2 and that of their charges is 5:3. Determine the ratio of the surface densities of charge of the two spheres.

1000 small water drops, each of radius r , combine and form a big drop. In this process, find decrease in surface energy.

64 small drops of mercury, each of radius r and charge q coalesce to form a big drop the ratio of the surface density of charge of each small drop with that of the big drop is

When 8 droplets of water of radius 0.5 mm combine to form a single droplet. The radius of it is ..........

A number of droplets, each of radius r , combine to form a drop of radius R . If T is the surface tension, the rise in temperature will be

A number of droplets, each of radius r , combine to form a drop of radius R . If T is the surface tension, the rise in temperature will be

Assume that 64 water droplets combine to form a large drop. Determine the ratio of the total surface energy of 64 droplets to that of large drop. Given, surface tension of water = 0.072 Nm^(-1) .