The equations of current and voltage in a circuit are as follows:
\[
i = 3.5 \sin\left(628t + \frac{\pi}{6}\right) \, \text{ampere}
\]
\[
v = 28 \sin\left(628t - \frac{\pi}{6}\right) \, \text{volt}
\]
Find:
(i) \text{Root mean square value of current},
(ii) \text{Time period},
(iii) \text{Phase difference between current and voltage.}