Finding current in electromagnetic field

[dev-hud]

A powerful electromagnet has a filed of 1.6 T and a cross-sectional area of .20 m^2. if we place a coil having 200 turns and a total resistance of 20 ohms around the eclectromagnet and then turn off the power to the electromagnet in 20ms, what is the current induced in the wire?

R = 20
N = 200 turns
A = .20 m^2
t= 20 ms
T = 1.6

THe problem i am having is figuring out which equations to use, i am assuming that I am going to have to arrange and rearagne equations but i have NO clue where to start or what equations to use in order to find current (I)

 

[jbsteele]

induced. The equation you need to use is Faraday's law, which states that the induced emf in a circuit is equal to the rate of change of the magnetic flux linkages through the circuit. In this case, the equation is:ε = -N * ΔΦ/ΔtWhere ε is the induced emf, N is the number of turns, ΔΦ is the change in magnetic flux, and Δt is the time over which the change in flux occurs. Using the given values, we can rearrange the equation to solve for current: I = ε/R Substituting the values from the problem gives us:I = (-200 * 1.6/0.02) / 20 I = -1600A