- #1
theshonen8899
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Homework Statement
A rectangular coil of wire has 65.0 turns and is 30.0cm by 43.0cm . Initially the plane of the coil is perpendicular to a uniform external magnetic field. It is then rotated till its plane is at an angle of 35.0∘ with that field. The magntude of the external field is 1.90T and total time to rotate the coil is 7.00×10−2s .
Calculate the magnitude of the average emf that is induced in the coil.
Homework Equations
Faraday's law
The Attempt at a Solution
So Faraday's law states that the induced emf is equal to [itex]\frac{-d\Phi_{B}}{dt}[/itex].
What I get is
A is area
A = (0.3m)(0.43m) = 0.129m^2
B is magnetic field
dB/dt = (1.90T)/(7.00*10^2 s) = 27.14 T/s
[itex]\frac{-d\Phi_{B}}{dt}[/itex] = -dB/dt * A * cos(35) = -2.87
N is # of turns
EMF = N * ([itex]\frac{-d\Phi_{B}}{dt}[/itex]) = 65 * -2.87 = -186
This number seems very large to me. Can anyone point out what I've done wrong?
Many thanks!