Chapter 2, Problem 2.4P

The secondary winding of a real transformer has a terminal voltage of $v_s\left(t\right)=282.8\sin 377t\text{V}\text{.}$

The turns ratio of the transformer is $100:200\left(a=0.50\right).$

If the secondary current of the transformer is $i_s\left(t\right)=7.07\sin \left(377t-36.87°\right)\text{}\text{A,}$ what is the primary current of this transformer? What are its voltage regulation and efficiency? The impedances of this transformer referred to the primary side are