Why is the value of EMF generated by a generator not zero at t = 0 s?

[songoku]

Homework Statement

This is not homework.

Let say coil of generator is in horizontal position (i.e. the direction of magnetic field of the magnet is perpendicular to the normal vector of the plane of the coil). The coil is then rotated so emf will be induced on the coil.

If I draw the graph of Φ (magnetic flux) against time, the shape will be like sin wave and if I draw the graph of emf against time, the graph will be like negative cosine wave so it means that the starting point of graph of emf against time will a certain negative value (let say -5 V).

Relevant Equations

ε = - N . dΦ / dt

Does this mean that initially there will be emf induced on the coil at t = 0 s?

Initially, at t = 0 s, the coil has not been rotated yet so based on Faraday's Law, there won't be any change in magnetic flux so why the value of emf is not zero at t = 0 s?

Thanks

 

[haruspex]

at t = 0 s, the coil has not been rotated yet

No, but it is rotating. The emf is created by movement, not position.

 

[songoku]

No, but it is rotating. The emf is created by movement, not position.

Thank you very much haruspex