Recent content by Szecska8

The answer I got on reddit, that helped me understand it. The total energy is given by (1/2μ_0)∫B2dV where the integral is taken over all space. Let us now split the space into a region X which contains the solenoid, and a region Y which is everything else. We can now write the integral as...

Can someone explain to me what the second integral represents and what is A?