Question

A point charge +10μC is fixed at the origin and another charge +10μC is at point A (4m, -3m). What is the work done by the electric force in moving the charge from point A to point B(2m,0)?

Answer 1

The square can be considered as one face of a cube of edge 10 cm with a centre where charge q is placed. According to Gauss’s theorem for a cube, total electric flux is through all its six faces.

Hence, electric flux through one face of the cube i.e., through the square,

Where, ∈0 = Permittivity of free space

= 8.854 × 10−12 N−1C2 m−2 q = 10 μC = 10 × 10−6 C

∴

= 1.88 × 105 N m2 C−1

Therefore, electric flux through the square is 1.88 × 105