Three charge `-q,+q` and `-q` are kept at the vertices of an equilateral triangle of `10cm` side.The potential at the mid point in between `-q,-q,` if `q=5muC` is

Options

A. `-6.4 xx 10^(5)V`
B. `-12.8 xx 10^(4)V`
C. `-6.4 xx 10^(4)V`
D. `-12.8 xx 10^(5)V`

Answer

D

Explanation

`V = V_(1) + V_(2) + V_(3), V_(1) = V_(2) = (1)/(4pi epsi_(0)) ((-q))/((a//2))`
`V_(3) = (1)/(4pi epsi_(0)) ((q))/(((sqrt3)/(2)))`