Question

What will be the total flux throguh the faces of the cube, Fig 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) In Fig, when a charge q is placed at corner A of the cube it is being shared equally by 8 cubes, Therefore, total flux through the faces of the given cube `= q//8 in_(0)`.
(b) When the charge q is placed at B, middle point of an edge of the cube, it is being shared equally by 2 cubes, therefore total flux through the faces of the given cube `= q//2 in_(0)`.
(d) Similarly, when charge q is placed at D the mid point of B and C, it is being shared equally by 2 cubes. Therefore, total flux through the faces of the given cube `= q//2 in_(0)`