更多"[单选题]电压和电流的瞬时表达式分别为u=220sin(ωt-10°)"的相关试题:
[单选题] 电压和电流的瞬时值表达式分别为u=220sin(ωt-10°)和i=5sin(ωt-40°),那么( )。
A.电流滞后电压40°;
B.电流滞后电压30°;
C.电压超前电流50°;
D.电压超前电流30°。
[单选题]有两个正弦量,其瞬时值的表达式分别为u=220sin(ωt-10°)V,i=5sin(ωt-40°)A。那么( )。
A.电压滞后电流30°
B.电压滞后电流50°
C.电流滞后电压30°
D.电流滞后电压40°
[单选题]电流电压瞬时值的表达式分别为：u=220sin(wt-100)V,i=5sin(wt-400)A,那么（ ）
A.电流滞后电压400
B.电流滞后电压300
C.电压超前电流500
[单选题]䈁4】有两个正弦量,其瞬时值的表达式分别为:u=220sin(ωt-10°),i=5sin(ωt-40°),可见,( )。 ( )
A. 电流滞后电压40°
B. 电流滞后电压30°
C. 电压超前电流50°
D. 电流超前电压30°
[判断题]纯电感正弦交流电路中的瞬时功率等于电流瞬时值与电压瞬时值的乘积
A.正确
B.错误
[单选题]已知某一电流的复数式I=(5-j5)A，则其电流的瞬时表达式为（ ）。
A.i=5sin(ωt一π/4)A
B.i=5sqrt(2)sin(ωt+π/4)A
C.i=10sin(ωt一π/4)A
D.i=5sqrt(2)sin(ωt一π/4)A
[单选题]在交流电路中，电压瞬时值和电流瞬时值的乘积叫做（）
A.平均功率
B.总功率
C.瞬时功率
D.以上都错
[单选题]
已知工频电压有效值和初始值均为380V，则该电压的
瞬时值表达式为（）。
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[单选题](Lb5A2031).交流电路中，电压瞬时值与电流瞬时值乘积称为( )
A.有功功率
B.视在功率
C.瞬时功率
D.功率
[判断题]感抗不能代表电压与电流瞬时值的比值。
A.正确
B.错误
[单选题](Lc5A2113).电压的瞬时值表达式为u＝110sin(ωt－π／3)(V)，电压的有效值为( )
A.110V
B.110V／
C.110V／2
D.－π／3
[判断题] 在纯电阻电路中,电压和电流瞬时值符合欧姆定律。
A.正确
B.错误
[多选题]三相对称正弦电压，当A相电压初相φ=0时。下列瞬时值表达式正确的是(___)。
A.uA=√2Usin(wt)
B.uB=√2Usin(wt-120°）
C.uC=√2Usin(wt+120°)
D.UA=U∠0°V
[判断题]某部分电路的端电压瞬时值为u，电流的瞬时值为i，并且两者有一致的正方向时，其瞬时功率p＝ui，则当p＞0时，表示该电路向外部电路送出能量；p＜0时，表示该电路从外部电路吸取能量。()
A.正确
B.错误
[判断题]
从电压、电流瞬时值关系式来看，电感元件属于动态
元件。
A.正确
B.错误
