A +ve point charge of magnitude q is located on the y−axis at a point of y=+d and another −ve charge of same magnitude is located on the point y=−d. A third +ve charge of same magnitude is located at some point on x−axis. (1)− what is the magnitude and direction of the force on third charge ? (a)− when its located on the origin. (b)− when its coordinate is x. (2)− show that when x is large compared to distance d, the force in (b) is inversely proportionalto the cube of the distance from origin.