Question

Four objects W, X, Y and Z, each with charge +q are held fixed at four points of a square of side d as shown in the figure. Objects X and Z are on the midpoints of the sides of the square. The electrostatic force exerted by object W on object X is F. Then the magnitude of the force exerted by object W on Z is ______.

Options

• `F/7`

• `F/5`

• `F/3`

• `F/2`

Answer 1

Four objects W, X, Y and Z, each with charge +q are held fixed at four points of a square of side d as shown in the figure. Objects X and Z are on the midpoints of the sides of the square. The electrostatic force exerted by object W on object X is F. Then the magnitude of the force exerted by object W on Z is `bbunderline(F/5)`.

Explanation:

Force on X by W is F = `(kq^2)/(d//2)^2`

= `(4kq^2)/d^2`

`WZ = sqrt(d^2 + (d//2)^2`

= `sqrt((5d^2)/4`

Force on Z by W is F' = `(kq^2)/((5d^2)/4)`

= `(4kq^2)/(5d^2)`

= `F/5`