Four charges are arranged at the corners of a square as shown in the figure. The direction of electric field at the centre of the square is along

Given data: Four charges are there. 

Concept Used: Electric field 

Detailed Solution:

Solve it by put an imaginary charge Q at the center of the square and now we calculate the force acting on it due to all the charges.

let the force due to charge $+q$ is $K\left(a\hat{i}-a\hat{j}\right)$

let the force due to charge +2 q is $K\left(-2a\hat{i}-2aj\right)$

let the force due to charge +3 q is $K\left(-3a\hat{i}+3aj\right)$

let the force due to charge $+4 q$ is $K\left(4a\hat{i}+4a\hat{j}\right)$

$\text{Thus net force on the charge}$ =$4Ka\hat{j}$

Thus the net direction of EF is along DC