A point charge +Q is placed at the centroid of an equilateral triangle. When a second charge +Q is placed at a vertex of the triangle, the magnitude of the electrostatic force on the central charge is 8 N. The magnitude of the net force on the central charge when a third charge +Q is placed at another vertex of the triangle is

Options

A. zero
B. 4N
C. `4sqrt(2)N`
D. 8N

Answer

D

Explanation

`R=sqrt(8^(2)+8^(2)+2.8.8 cos120^(@))=8N`