Khi $L $ thay doi de $U_{L}max$ thi $U vuong pha vs U_{RC}$Khi $U$ triet tieu thi $U_{RC}$ o vi tri bien nen $U_{oRC}=100V$
Vay $U_{RC}=100cos(100\pi t\pm \frac{\pi }{2})$
Co $\overrightarrow{u_{L}}=\overrightarrow{u}-\overrightarrow{u_{RC}}$
Bam may tinh nhu pt dddh co dk $U_{oL}=100\sqrt{2}V$
Vay $U_{L}=100V$
Dap an C