Magnitude of EMF when the armature coil is in different positions?

[Dreaam]

I am currently studying for a Magnetism and Electricity exam coming up. I was just wondering, within the topic of Electromagnetic induction; my textbook states that if an armature coil of some sort -either from an AC or DC generator was placed horizontally into a magnetic field that is also horizontal, (so the North pole on the left and south pole on the right, meaning the magnetic field lines would be going --->), then the EMF would be at a maximum. If the coil was vertical the EMF would be a minimum. This picture may explain it better: http://www.rfcafe.com/references/El...ourses/images/electricity-navy-basics-126.jpg

I unfortunately don't understand this and there is no further explanation other than those statements. Could somebody please explain to me why the EMF would be a maximum when the armature coil is horizontal.

Relevant formulas

EMF = BLV
EMF = -(N*Δϕ)/Δt

Thank you for your time.

 

[rude man]

Because the rate of change of the magnetic flux is maximum when the coil is 'horizontal'. The flux itself is zero but the rate of change of flux is maximum:
flux = BA sin(wt), coil is 'horizontal' at t=0 so flux(0) = 0
but d(flux)/dt = wBAcos(wt) which is maximum at t=0 so emf = wBA at t=0.