Question

Four charges are placed at the four corners of a square of side 15 cm. The charges on the upper left and right corners are +3 µC and -6 µC respectively. The charges on the lower left and right corners are -2.4 µC and -9 µC respectively. The net electric force on -6 µC charge is:

25 N, 780 above the -ve x- axis


25 N, 780 below the -ve x- axis


13 N, 310 below the +ve x- axis


18 N, 750 above the +ve x- axis