Question

Two conducting spheres with the same charge Q are separated by an infinite distance. Sphere A has a radius of 10 cm while sphere B has a radius of 20 cm. At what distance from the centers of the spheres would the magnitude of the electric field be the same?

(A) 15 cm from A and 15 cm from B 

(B) 20 cm from A and 34 cm from B

(C) 20 cm from A and 40 cm from B 

(D) 30 cm from A and 40 cm from B

(E) 40 cm from A and 40 cm from B

Answer 1

The correct option is: (E) 40 cm from A and 40 cm from B

Explanation:

Once outside the spheres, they act as point charges and their difference in size is irrelevant.