An alternating current (ac) generator produces a peak emf $E_{0}$ and periodic time $T$. What are the peak emf and periodic time when the frequency of rotation is doubled?

Peak emf: $2E_{0}$, Periodic time: $2T$

Peak emf: $2E_{0}$, Periodic time: $\frac{T}{2}$

Peak emf: $E_{0}$, Periodic time: $2T$

Peak emf: $E_{0}$, Periodic time: $\frac{T}{2}$