Aqa Physics Electromagnetic Induction

Basically i am having trouble understanding electromagnetic induction and Lenz's Law. I am aware that when a magnet enters a conducting coil an is e.m.f induced proportional to flux linkage, and that a current carrying conductor has its own magnetic field - hence why when the current is induced in the coil a magnetic field is made around the coil to oppose the motion of the magnet and conserve the laws of energy. But the thing i dont understand is that current is only induced in a closed circuit, e.g a conducting rod will induce e.m.f but no current - if no current is induced in the conducter than it will not have its own magnetic field? And therefore where does the force come from what opposes it?

Reply 1

mik1a

The flux linkage is defined in terms of closed loops. The flux linkage describes the amount of magnetic flux that passes through a closed loop, and the EMF tells you the electric field induced around that loop (which will cause your current to circulate).

If you don't have a loop, you don't have a flux linkage, no flux linkage, no EMF, no current, no force!

Reply 2

DannySmith420

Original post by mik1a

The flux linkage is defined in terms of closed loops. The flux linkage describes the amount of magnetic flux that passes through a closed loop, and the EMF tells you the electric field induced around that loop (which will cause your current to circulate).
If you don't have a loop, you don't have a flux linkage, no flux linkage, no EMF, no current, no force!

So is it not possible for an emf to be induced but no current is induced?

Reply 3

mik1a

The key requirement here for an EMF is a closed loop. As long as you have that, you will have an EMF. Now the closed loop might be made of some insulating material, so no current will flow. In this case you can have an EMF with no induced current (and therefore no force).

In the case of a straight length of wire or a pole, you don't have a closed loop, so no EMF.