 Wires are bendy. You can twist them into all sorts of shapes. Current-carrying wires generate magnetic fields. So if you combine these two, what will happen? It can get complicated very fast, as you might imagine. So let's look at a simple loop first. We found the electric field around two charged particles by looking at the electric field around individual particles and then adding them together. We can apply the same idea to the magnetic field around a loop. Where we look at the magnetic field of each individual part of the wire and then add them together. I can find the magnetic field around each individual part of the wire with the right hand rule. So if I twist this wire into a loop and then rotate it so one side faces you and one side faces me. Now let's say I had a current in this wire going towards me down the bottom, up, up the back, towards you on top and down the front. Now because the current goes towards me down the bottom, the magnetic field is clockwise and up the top the current goes towards you and the magnetic field is anticlockwise. You'll notice that my fingers always point towards the right on the inside of the loop and it always points towards the left on the outside of the loop. This tells us that the overall magnetic field because of the loop points to the right on the inside of the loop and points to the left on the outside of the loop. Here's a 2D visual representation of the magnetic field around a loop. For the side-on view that we were just looking at, the magnetic field due to the bottom bit of the loop would be circular in a clockwise direction. The top bit of the loop would also have a circular magnetic field. However, it would be anticlockwise since the current is travelling in opposite directions. And as we've previously discussed, the magnetic field would be stronger in the middle due to all parts of the current reinforcing it, pointing to the right. Around the outside it would be weaker, pointing to the left. So the magnetic field around a loop looks like this. You'll notice that this looks similar to the magnetic field around a bar magnet, except more squashed. If we lie the ring flat and look at the magnetic field from this perspective, we get the bottom bit of the ring generating a magnetic field going into the page on the inside of the loop and out of the page outside of the loop. The next bit of the ring would do the same, and so on. Overall, you would end up with this field, where the field lines are denser inside the ring and sparser outside the ring.