单项选择题
图所示正弦交流电路中,电流i=5sin(314t+30°)A,其端电压u=4sin(314t-60°)V,则其复阻抗Z应为()
A.0.8≤90°Ω B.0.8≤30°Ω C.1.25〈90°Ω D.1.25≤30°Ω
A.8Ω B.2Ω C.5Ω D.7Ω
A.发出5W B.吸收5W C.发出2W D.吸收2W