Four charges q,-2q,+2q,-q are placed respectively at the corners of a square of side a cm .what will be the magnitude of electroc field at the centre of square

Q. Four charges $2q,q,–q$ and $–q$ are placed at corners of a square of side length $a.$ The electrostatic potential at the centre of the square will be equal to

$[$0.77 Mark$]$

Q. Four point charges $+q,–q,–2q$ and $+2q$ are kept at the corners of a square of side length $a$ as shown. Then

Q. Four point charges -Q,-q,2q and 2Q are placed, one at each corner of the square. The relation between Q and q fo which the potential at the centre of the square is zero, is

Q. Four point charge -Q, -q, 2q and 2Q are placed, one at each corner of the square. The relation between Q and q for which the potential at the centre of the square is zero is:

Q. Four point charges $-Q,-q,2q$ and $2Q$ are placed, one at each corner of the square. The relation between $Q$ and $q$ for which the potential at the centre of the square is zero is
[NEET-2012 (Pre)]