what is the work done in moving a 2 micro coulomb point charge from corner A to corner B of a square' when a 10 mc charge exists at the centre of a square?

points A and B are equidistant from centre. so they are equipotential points. No work is done in moving 2 micro C charge between equipotential points.

W = a(V_B - V_A)

V_A = V_B

W = 0