question_answer 13)

A cube of side b has a charge q at each of its vertices. Determine the potential and electric field due to this charge array at the centre of the cube. 

Answer:

(i) Distance of the centre of the cubs from vertex is half of the diagonal of the cube                 i.e.,                   Using  for 8 charges at 8 vertices, we get                                                 (ii) From symmetry, it is clear that electric field at centre of the cube is zero.