Answer to Question #320054 in Electricity and Magnetism for Pearl

Question

Two spheres of equal mass and equal charge are separated at a distance r.

(a) Derive an expression for the quantity of charge that must b on each sphere so that the spheres are in an equilibrium where attractive and repulsive forces are balanced.

(b)How would doubling the distance between spheres affect the expression for the value of q from the previous problem. Explain.

Answer 1

Answer

a) The size of the force varies inversely as the square of the distance between the two charges. Therefore, if the distance between the two charges is doubled, the attraction or repulsion becomes weaker, decreasing to one-fourth of the original value.

b) If we double the charge q 1 , for instance, then the force is doubled. If we double the distance between the objects, then the force between them decreases by a factor of 2.