Which of the following statement(s) is/are correct?

Options

A. If the electric field due to a point charge variesas `r^(-2.5)` instead fo `r^(-2)`, then the Gauiss law will still be valid.
B. The Gauss law can be used to calculate the field distributed around on electric dipole.
C. If the electric field between two points charges is zero somewhere , then the sign of the two charges is not the same.
D. The work doen by the external force in moving a unit positive charge from point `A` at potential `V_(A)`to point `B` at potential `V_(B)` is `(V_(B) - V_(A))`.

Answer

D

Explanation

(i) Gauss's law ahs been deduced with the help of Coulomb's law.According to which, electric fileld due to a point charge, `E prop 1//r^(2)` and not `E prop 1//r^(2.5)`. Thus option (a) is wrong.
(ii) The Gauss's law can not be used to calculate the field distribution around an electric dipole as the total charge enclosed by the gaussain surface around dipole is zero. Thus,o[tion (b) is wrong.
(iii) If two charges are of the same sign, the electric field is zero somewhere on the line joining the two charges, inbetween the two charges. Thus, option (c ) is wrong.
(iv) option (d) is correct if work doen is against the elecatrostatic force.