question_answer

A cube has point charges of magnitude -q at all its vertices. Electric field at the centre of the cube is:

A)  \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{6q}{3{{a}^{2}}}\]           

B)         \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{8q}{{{a}^{2}}}\]

C)         zero                                     

D)         \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{-8q}{{{a}^{2}}}\]

Correct Answer: C

Solution :

opposite to it. So, the net electric field at centre of the cube is zero.