# Coil moving in B-field

1. Oct 26, 2012

### MrPacane

1. The problem statement, all variables and given/known data

A 25-turn coil has a radius of 1 cm and it is carrying a current of 1 A. The coil is in a constant B-field of 1 T (directed along the coil's axis). The coil is moving perpendicularly to the B-field at a speed of 1 m/s.

a) Is there an Electromotive force induced in the coil?
b) How much electrical power needs to be provided to the coil under the operating conditions described?

2. Relevant equations

- Lorentz Force Law

3. The attempt at a solution

a) I don't think there is an emf induced in the coil because its cross-sectional area stays the same, and there's no variation of the B-field.
b) Normally, I would use P = I²R but the resistance of the coil is not given...

Am I correct?

Thanks!

2. Oct 26, 2012

### BruceW

question 'a' is a tricky one. You need to try again. There is a motional emf. Think of the charge carriers in the wire, and what is their velocity, therefore should they experience an emf due to the magnetic field?

And for part b) I'm not certain what they mean. You cannot calculate the power due to the 'original' current of 1 amp. So maybe they want you to do a calculation using the answer of part a)