If the voltage and current $($both are rms values$)$ supplied to a circuit or load by a source are $V_s(rms)=\frac{7}{{?}_{50}}$ volt and $Is(rms)=\frac{13}{{?}_{-}}20A.$ Determine the following:

a$)$ The complex power

b$)$ The real power

c$)$ The reactive power

d$)$ The apparent power

e$)$ The power factor angle and power factor.