# Homework Help: Number of Turns on a Loop

1. Apr 20, 2010

### anonymousphys

1. The problem statement, all variables and given/known data
Do the number of turns on the loop magnify the current or the magnetic field?

2. Relevant equations

3. The attempt at a solution
I believe its a magnetic field, but can someone confirm this?

Thanks for any replies.

2. Apr 20, 2010

### hermy

If a fixed current I is passed through the coil, the magnetic field would be $$\mu$$nI.

But due to self inductance, the current in the coil changes. As you would already know, self inductance depends on the no. of turns in the coil.

3. Apr 20, 2010

### anonymousphys

So, because of the turns on the coil, the magnetic field increases, but does the magnetic field increase because the current in the conductor creating the magnetic field increases? Or is there another reason for the change in magnetic field?

4. Apr 20, 2010

### Antiphon

This is a poorly defined problem. Assuming you have a loop of wire with N turns. What happens with a fixed current if you add more turns?

Each turn adds more flux down the axis of the loop. The current doesn't change because it's fixed.

If you are talking about inductance, that goes up as the square of the number of turns.

If you are talking about the current through an inductor it is equal to the time integral of the applied voltage divided by the inductance.