Consider a closed loop C in a magnetic field, Fig. The flux passing through the loop is defined by choosing a surface whose edge coincides with the loop and using the formula `phi = B_(1) .dA_(1) + B_(2). Da_(2) +`……..Now if we chose two different surfaces `S_(1)` and `S_(2)` having C as their edge, would we get the same answer for flux. Justify your answer.

Explanation

The magnetic flux linked with the surface can considered as the number of magnetic field lines passing through the surface. So, let `dphi=BA` represnets magnetic lines in an area A to B.
By the concept of continuity of lines B cannot end or start in space, therefore the number of lines passing through surface `S_1` must be the same as the number of lines passing through the surface `S_2`. Therefore, in both the cases we gets the same answer for flux.