Magnetic flux, emf in a generator woe (1 Viewer)

[karnage]

Hi guys, got abit of a point im finding hard to get my head around.

From pg 138 of Jacaranda Physics referring to the magnetic flux and emf graphs against time.

"The flux threading the coil is at a maximum value. The emf is zero, as the gradient of the flux versus time graph is zero which means that there is no change in flux htrough the coil at this instant"

Im well aware that emf will only be induced in a changing rate of magnetic flux but i would have thought that when the flux is at maximum it would produce a large amount of emf as it changes.

Or maybe im getting confused with something simple here, if so could someone please point it out. Thanks in advance guys.

 

[nick3157]

Double check with your teacher before you take my word for it. See fig 8.3 on p137. Remember, it's flux change which causes an induced emf. So on the flux vs time graph, the only point at which there is no flux change is when the gradient =0 (when the red line is horizontal). That is why when the gradient of the flux-change line is horizontal, the corresponding emf value is 0.