An alternator produces an emf given by ε(t)=170sin(100πt) volts, where t is in seconds.
(i) Calculate the frequency and the period of the emf.
(ii) Determine the smallest positive time after t=0 when the emf first reaches +85V.
(iii) Calculate the time interval between this instant and the next instant when the emf attains its first negative maximum value.