Question

Which of the following statements is/are correct ?

(A) Electric field calculated by Gauss law is the field due to only those charges, which are enclosed inside the Gaussian surface.

(B) Gauss law is applicable only when there is symmetrical distribution of charge.

(C) Electric flux through a closed surface is equal to total flux due to all the charges enclosed within that surface only.

(D) None of these

Answer 1

Since, electric field at a point is equal to electric flux passing per unit area, therefore,

is the net flux emanating from a closed surface. Though net flux through the closed surface depends upon the charges enclosed in that surface only but electric field E at a point depends not only upon charges enclosed but it depends upon charges lying outside the surface also. Hence (A) is wrong.

Gauss law is applicable to a closed surface. The surface may have any shape. It means, it is a general law. Hence (B) is wrong.

Gauss law is

It means, net flux through a closed surface depends upon Σq. But it is equal

to net charge enclosed within the surface only. Hence (C) is correct. Obviously (D) is wrong.