# Consider a closed loop C in a magnetic field as shown in the figure

#1

Consider a closed loop C in a magnetic field as shown in the figure. The flux passing through the loop is defined by choosing a surface whose edge coincides with the loop and using the formula Now, if we choose two different surfaces having C as their edge, would we get the same answer for flux. Justify your answer.

#2

The magnetic flux linked with the surface can be considered as the number of magnetic field lines passing through the surface. So, let d$\phi$ = BA represents magnetic lines in an area A and B.
By the concept of continuity of magnetic field lines, it 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 get the same answer for flux.