*Originally posted by dr *

10. a (emf = change in the rate of flux passing through the area of the coil)

Dear Sir/Miss,

You might like to rethink Q10.

emf is the rate of change of flux blablabla. Because the coil rotates in a constantly circular nature, the flux in the area of the coil varies sinusodially with time {something like flux = k*sin(at + b)}. As we all know, a sine curve is steepest at flux=0, and horizontal or stationary at max/min flux.

And we also know the rate of change of flux (i.e. d(flux)/dt) is basically the gradient of the curve at any specific point (t,flux).

Thus we have max magnitude emf at P, R, T, and zero magnitude at Q, S.