A sphere carrying a charge of `-20 mu C` is placed at a certain distance from another identical sphere carrying a charge of `+80 mu C`.The two spheres are brought in contact, separated and kept in their original positions.The ratio of the forces between them before and after they are in contact is

Two identical spheres carrying charges -9 mu C and 5 mu C respectively are kept in contact and then separated from each other. Point out true statement from the following. In each sphere

Two spheres are separately charged and then brought in contact, so

Two identical conducting sphere carrying different charges attact each other with a force F when placed in air medium at a distance d apart. The spheres are brought into contact and then taken to their original positions. Now, the two sphere repel each other with a force whole magnitude is equal to the initial attractive force. The ratio between initial charges on the spheres is

Two identical metal spheres posses +60C and -20C of charges .They are brought in contact and then separated by 10cm .the force between them is

Two tiny conducting spheres are identical any carry charges of -20.0 mu C and +50.0 muC . They are separated by a distance of 2.50 cm. The spheres are brought into contact and then separated to a distance of 2.50 cm. Determine the magnitude of the force that each sphere now experiences, and state whether the force is attractive or repulsive.

Two identical balls having like charges and placed at a certain distance apart repel each other with a certain force. They are brought in contact and then moved apart to a distance equal to half their initial separation. The force of repulsion between them increases 4.5 times in comparision with the initial value. The ratio of the initial charges of the balls is