Four point charges qA = 2μC, qB = -5μC, qC = 2μC and qD = -5μC are located at the corners of a square ABCD of side 10 cm. What is the force on a charge of 1μC placed at the centre of the square.

Step 1: Identify the given charges and their positions. The charges at the corners of the square are: • $q_A = 2 \, \mu\text{C}$ • $q_B = -5 \, \mu\text{C}$ • $q_C = 2 \, \mu\text{C}$ • $q_D = -5 \, \mu\text{C}$ A charge $q_O = 1 \, \mu\text{C}$ is placed at the center $O$ of the square. The side length of the square is $10 \, \text{cm}$.

Step 2: Determine the distance from each corner to the center. The distance from each