$16.$ A transformer has $1200$ primary turns and $200$ secondary turns. The primary and secondary resistances are $0\mathrm{.}2$ and $0\mathrm{.}02$ respectively and the corresponding leakage reactances are $1\mathrm{.}2$ and $0\mathrm{.}05$ respectively. Calculate $($a$)$ the equivalent resistance, reactance and impedance referred to the primary winding, and $($b$)$ the phase angle of the impedance.