# Current through a coil in a magnetic field

1. Sep 13, 2009

### cheeseboy

Question:

A coil of 90 turns, of resistance 6 ohm and area 28 cm² moves from a
uniform magnetic field of 0.02 Tesla to one of 0.42 Tesla in 3.0 second.
What average current flows in the wire (in amp) ?

Relevant equations:

EMF= (Area * Rate of change of magnetic flux) * Number of turns

I = EMF/Resistance

Attempted Solution:

EMF= ((0.28^2) * ((0.42-0.02)/3)) * 90 turns = 3.36

I = EMF/Resistance = 3.36/6 = 0.56 amps (i believe this is correct)

however answer given is 0.0056 amps where am I missing this factor of 100?

Last edited: Sep 13, 2009
2. Sep 13, 2009

### Hootenanny

Staff Emeritus
$$28\;cm^2 \neq 0.28\;m^2$$