# Force of a changing magnetic field

1. Jul 16, 2015

### DCN

By Faraday's Law, we know that a changing magnetic field can induce a potential around a loop of wire and it follows that any charges in the loop will experience a force, otherwise they wouldn't move. Therefore a changing magnetic field exerts a force on stationary charges.

How do you tell the direction of this force is the charge is not in a loop of wire?

2. Jul 17, 2015

### Noctisdark

You also use Faraday law, ∇x E = -∂B/∂t, and solve this for E, but remember that the magnetic field is gone yet, so you have lorentz force, F = q(E + |v x B|), however if the charge is stationnary, then just be force it start moving F = qE, F⊥B just because E⊥B (because of the curl), by this you can see that the force can be in any direction even in the direction of the loop if you put the magnetic field in the right angle,once it started moving perpenducular forces are further applied, this you can expect it to be in the direction for the loop (curvature)of the wire

3. Jul 17, 2015

### DCN

How would you isolate E from Faraday's law?

4. Jul 17, 2015

### Noctisdark

It's a partial differential equation,