A charged metallic sphere A is suspended by a nylon thread. Another charged metallic sphere B carried by an insulating handle is brought close to A such that the distance between their centres is 10 cm. The resulting repulsion of A is noted (for example, by shinning a beam of light and measuring the deflection of its shadow on a calibrated screen). Spheres A and B are touched by uncharged spheres C and D respectively. C and D are then removed, and B is brought closer to A to a distance of 5.0 cm between their centres. What is the expected repulsion of A on the basis of Coulomb's law? Spheres A and C and spheres B and D have identical sizes. Ignore the sizes of A and B in comparison to the separation between their centres.

1 Answer