- #1

theshonen8899

- 10

- 0

## 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!