Câu hỏi 33

Đáp án D

Theo bài ra ta có

  \(\begin{array}{l}U = E = k.n;{U_1} = k.3n;{Z_{L1}} = a.3n\\{I_1} = \frac{{k.3n}}{{\sqrt {{R^2} + {{(a.3n)}^2}} }} = 3;\,\cos {\varphi _1} = \frac{R}{{\sqrt {{R^2} + {{(a.3n)}^2}} }}\\4{R^2} = {R^2} + {(a.3n)^2} =  > {(a.3n)^2} = 3{R^2} =  > {(a.n)^2} = \frac{{{R^2}}}{3}\\kn = \sqrt {{R^2} + 3{R^2}}  = 2R\\{I_2} = \frac{{k.n}}{{\sqrt {{R^2} + {{(a.n)}^2}} }} = \frac{{2R}}{{\sqrt {{R^2} + {{\frac{R}{3}}^2}} }} = \sqrt 3 \end{array}\)