Q. Four identical charges Q are fixed at the four corners of a square of side *a*. The electric field at a point P located symmetrically at a distance a/√2 from the center of the square is

(a) $ \displaystyle \frac{Q}{2\sqrt2 \pi \epsilon_0 a^2 } $

(b) $ \displaystyle \frac{Q}{\sqrt2 \pi \epsilon_0 a^2 } $

(c) $ \displaystyle \frac{2\sqrt2 Q }{ \pi \epsilon_0 a^2 } $

(d) $ \displaystyle \frac{\sqrt2 Q }{ \pi \epsilon_0 a^2 } $

Ans: (b)