The diagram shows a flat rectangular coil of wire rotating counter-clockwise at a constant angular velocity ω \omega\,ω in a uniform magnetic field between two permanent magnets.
At time t=0t = 0t=0, the coil starts in the vertical position, where its plane is perpendicular to the magnetic field.
Which letter on the graph of induced electromotive force, ε\varepsilonε, against time, ttt, represents the output of the generator at the instant shown in the diagram?
A
B
C
D