Consider the following simple generator. A bar permanent magnet is rotating at a constant angular speed by some external means. Two coils of wire are placed in the same plane as the axis of the bar magnet. The two coils are placed in the same line. The two coils are connected together. This is shown in the following GIF image.
The magnetic flux through the coils changes in time. It is maximum in absolute value when the magnet is aligned with the coils, and zero when the magnet is perpendicular to the axis of the coils (because at this instant the magnetic field lines are parallel to the loops of wire of the coils). The flux changes sinusoidally in time. Thus, the rate of change of the flux is zero (and therefore the induced EMF is also zero as per Faraday's law) when the flux is maximum in absolute value (i.e. when the magnet is aligned with the coils), and the rate of change of flux is maximum in absolute value (and therefore the induced EMF is also maximum in absolute value) when the flux is zero (i.e. when the magnet is perpendicular to the axis of the coils).
But, the figure below shows the opposite: according to the figure, the EMF is zero when the magnet is perpendicular to the axis of the coils, and it is maximum in absolute value when the magnet is aligned with the coils.
Figure 1. Image source: The Engineering Mindset.
Is the EMF of the figure wrong, or am I wrong?
(I wasn't sure if I should've posted this question here on the Physics Stack Exchange.)
My reasoning would also explain why in the generator of the following figure, the waveform of the induced EMF is the one shown.
Figure 2. Image source: Sears and Zemansky's University Physics: with Modern Physics (13th edition) by Hugh D. Young and Roger A. Freedman.
