When a rectangular coil is rotated in a uniform magnetic field about an axis passing through its centre and perpendicular to the field,the emf induced in the coil varies

Which statement is correct for the phenomenon of periodic electromagnetic induction?

$A$ circular coil of resistance $R$,area $A$,and number of turns $N$ is rotated about its vertical diameter with angular speed $\omega$ in a uniform magnetic field of magnitude $B$. The average power dissipated in a complete cycle is:

Discuss the principle and construction of an $A.C.$ generator (dynamo). Derive the formula for the induced $emf$ in an $A.C.$ generator.

$A$ coil of area $25 \; cm \times 10 \; cm$ having $300$ turns is rotated in a magnetic field of $4 \times 10^{-2} \; T$ with an angular speed of $50 \; rps$. What is the maximum $emf$ induced (in $\pi \; V$)?

$A$ square-shaped coil of area $70 \, cm^2$ having $600$ turns rotates in a magnetic field of $0.4 \, Wb/m^2$,about an axis which is parallel to one of the sides of the coil and perpendicular to the direction of the field. If the coil completes $500$ revolutions in a minute,the instantaneous emf when the plane of the coil is inclined at $60^{\circ}$ with the field will be $..........V$. (Take $\pi = \frac{22}{7}$)