Electromagnetic Induction Questions

In an AC generator, a coil with $N$ turns, all of the same area $A$ and total resistance $R$, rotates with frequency $\omega$ in a magnetic field $B$. The maximum value of emf generated in the coil is:

The flux linked with a coil at any instant $t$ is given by $\varphi =10t^2-50t+250$. The induced emf at $t=3\text{s}$ is: