Question

What will be the total flux through the faces of the cube, with side of length a if a charge q is placed at (a) A : a corner of the cube (b) B : mid-point of an edge of the cube (c ) C : center of a face of the cube (d) D : mid-point of B and C.

Answer 1

(a). There are eight corners in a cube so, total charge for the cube is `(q)/(8)`. ltbr. Thus, electric flux at `A=(q)/(8epsi_(0))` ltb rgt (b) When the charge q is plae at B, middle point of an edge of the cube, it is being shared equally by 4 cubes. therefore, total flux through the faces of the given cube `=q//2epsi_(0)`
(c). When the charge q is placed at C, the centre of a face of the cube, it is being shared equally by 2cubes. therefore, total flux through the faces of the given cube `=q//2epsi_(0)`
(d). Similarly, when charge q is placed at Q, the mid-point of B and C, it is being shared equally by 2 cubes. therefore, total flux through thef aces of the given cube `=q//2epsi_(0)`.