Calculation of Electric Potential at the Centre of the Square
Electric potential at a point due to multiple point charges is the algebraic sum of the potentials due to individual charges at that point. The electric potential at the centre of the square can be calculated as follows:

Step 1: Calculate the Electric Potential due to each Charge
- Electric potential due to a point charge is given by V = k * q / r, where k is the electrostatic constant, q is the charge, and r is the distance from the charge to the point.
- Calculate the electric potential due to each charge at the centre of the square using the formula.

Step 2: Find the Total Electric Potential at the Centre
- Add up the electric potentials due to all four charges to find the total electric potential at the centre of the square.
- Since electric potential is a scalar quantity, consider the signs of the charges while adding the potentials.

Step 3: Perform the Calculation
- Substitute the given values (charges and side length of the square) into the formula and calculate the electric potentials due to each charge.
- Add up all the potentials to find the total electric potential at the centre of the square.

Step 4: Final Result
- The final result will be the electric potential at the centre of the square due to the four given charges.
By following these steps, you can calculate the electric potential at the centre of the square accurately, taking into account the contributions of all the charges placed at the corners of the square.