(Solved): An ac generator produces emf E=Emsin(dt /4 ), where Em=30.0V and d=373rad/s. ...

An ac generator produces emf $\mathcal{E}={\mathcal{E}}_{\mathrm{m}}\sin ({?}_{d}t$ $??/4$ ), where ${\mathcal{E}}_{\mathrm{m}}=30.0\mathrm{V}$ and ${?}_d=373\mathrm{rad}/\mathrm{s}$. The current in the circuit attached to the generator is given by $i(t)=I\sin \left({?}_{d}t+?/4\right)$, where $I=631\mathrm{mA}$. (a) At what time after $t=0$ does the generator emf first reach a maximum? (b) At what time after $t=0$ does the current first reach a maximum? (c) The circuit contains a single element other than the generator. Is it a capacitor, an inductor, or a resistor? (d) What is the value of the capacitance, inductance, or resistance, as the case may be? (a) Number Units (b) Number Units