(Everyone lives by selling something. In the light of this statement), teachers live by selling knowledge, philosophers by selling wisdom and priests by selling comfort.
【单选题】在纯电感交流电路中,已知感抗 X L = 4Ω,当电流i= √2 sin(314t+30°)A,则电压为( )。 A. u= 4√2 sin(314t+30°)V B. u= 4√2 sin(314t+120°)V C. u= 4√2 sin(314t-60°)V D. u= 4√2 sin(314t+60°)V