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## Homework Statement

A rectangular coil with

*a*and

*b*sides can rotate around the axis

*AA'*with angular velocity

*ω.*It is in a magnetic field as in figure.

Calculate the flux of B when the coil is orthogonal to the axis AA'. Calculate the [itex]\epsilon_{max}[/itex] and express the position of the coil.

## Homework Equations

[itex]\epsilon = -\frac{d}{dt} \phi_B[/itex]

## The Attempt at a Solution

The flux when the coil is orthogonal to the axis AA' is 0.

[itex]\phi_B = NBabcos\theta [/itex]

[itex]\theta[/itex] is 90°, so the flux is 0.

Now I calculate the emf.

[itex]\epsilon = -\frac{d}{dt} \phi_B = NBab\omega sin(\omega t) [/itex]

The emf is max when [itex]sin(\theta)[/itex] is 1, so when [itex]\theta[/itex] is 90°.

Is it correct my procedure?

If yes, why emf is maximum when flux is 0?