【单选题】
已知某正弦电压的频率f=50Hz,初相角φ=30°,有效值为100V,则其瞬时表达式可为()。
A、u=100sin(50πt+30°)V
B、u=141.4sin(50πt+30°)V
C、u=200sin(100πt+30°)V
D、u=141.4sin(100πt+30°)V
A、u=100sin(50πt+30°)V
B、u=141.4sin(50πt+30°)V
C、u=200sin(100πt+30°)V
D、u=141.4sin(100πt+30°)V