Question

Four charges q,2q,q,-q are placed at the corners of a square.calculate the electric field at the intersection of diagonals of square of side 10 cm

Answer 1

Given in the question :-

side (r) = 10 cm = 0.1 m

Now Refer to the attachment

Here four point charges +q , 2q , +q , -q are given along with diagonal side 0.1 m .
Now  electric field at the intersection point of the diagonals of the square,
Hence the net electric field :-
E = k . ( + q + 2q + q  - q ) / r² 

E = k .3q / r²


Now put the values .

E = 9 × 10⁹ (3q) / (0.1 /√2)²  
E = 9 × 10⁹ × q  / 10⁻²
E =  9 × 10¹¹ ×  3q
$E = 3q (9 * 10^1^1 )$


Hence the value of the electric field is  $E = 3q (9 * 10^1^1 )$


Hope it Helps . :-)