问题 问答题 简答题

如下图所示电路中,已知电路中电流I2=2A,US=7.07V,求电路中总电流I、电感元件电压两端电压UL及电压源US与总电流之间的相位差角。

答案

参考答案:

设并联支路端电压为参考相量,则

1Ω电阻上通过的电流

总电流为:

即总电流有效值为2.828A

总电压:

因电感上电压相位为135°,所以其实部虚部数值相等,用凑数法求出总电压的角度为123°,则

电感上端电压为:

即总电压、电流之间的相位差角为78°,电路呈感性。

多项选择题
完形填空

III.完形填空(共20小题;每小题1分,满分20分)

阅读下面短文,掌握其大意,然后从各题所给的四个选项(A、B、C和D)中,选出最佳选项。

Last night, I was waiting for a taxi. After 5 minutes, I was  41 . The driver seemed to be angry. I asked him what the  42  was. He said he had just come from the airport without a  43 , which was basically $70 in lost fare.

Over the course of that ride, the anger slowly  44 . He mentioned he had read an article saying the  45  people are the ones that give, so he hoped he’d have more  46  to give in his life. I was starting to  47  being with him! We continued talking about why  48  is so beneficial both to the giver and the receiver and different ways to  49  it.

As we arrived at my destination, I  50  my fare. But I pulled out an extra $20 and said, “Since we’ve been talking about giving this whole time, I wanted to share that  51  with you. I’ve already paid my fare, but here’s an extra little bit. You can  52  it, since you’re already down $70 from the airport. But if you want to experience the  53  of the gift, then tell the next passenger in this taxi that their ride is a gift from another and they can  54  their gratitude in whatever way.”

The man turned toward me, tears in his eyes, and said, “Sir, I have a better  55 . You give that $20 to a  56  person around here and I’ll treat the next passenger with a  57  ride myself.”

Wow. This man was  58  10 minutes ago. I got out and walked around trying to find someone who needed help  59  heading to my destination.

It was an honor meeting that driver and  60  the lesson of how everyone is capable of giving.

41.A.gotten off          B.put down           C.called up         D.picked up

42.A.question          B.time               C.problem          D.cost

43.A.friend             B.stranger            C.driver                 D.customer

44.A.died out           B.appeared           C.died down         D.died off

45.A.happiest           B.poorest            C.richest            D.strongest

46.A.kindness           B.chances            C.suggestions         D.money

47.A.mind             B.stop               C.allow             D.enjoy

48.A.collecting          B.giving             C.receiving        D.existing

49.A.practise           B.explain             C.watch             D.consider

50.A.printed            B.recorded            C.paid            D.examined

51.A.adventure          B.information         C.language           D.feeling

52.A.refuse             B.raise               C.keep              D.spend

53.A.direction          B.power              C.weight            D.size

54.A.share             B.earn               C.forget             D.miss

55.A.gift               B.idea               C.opinion            D.ride

56.A.homeless           B.native             C.nice               D.brave

57.A.long              B.comfortable        C.free               D.safe

58.A.bored             B.tired              C.rude               D.angry

59.A.after              B.before             C.when              D.as

60.A.learning           B.preparing          C.finishing           D.providing