试题与答案

(2010•金华)黑夜看不见开关位置,为此小明设计了如图所示的电路.当单刀双掷开

题型:计算题

题目:

(2010•金华)黑夜看不见开关位置,为此小明设计了如图所示的电路.当单刀双掷开关S合向b时,照明灯亮、指示灯灭,避免指示灯费电;S合向a时,照明灯灭、指示灯亮,显示开关位置(S只能处于这两种状态).他在如图所示方框中完成指示灯和电阻丝的连接电路,指示灯规格为“10V,1W”.

(1)照明灯正常工作时的电阻是多少?

(2)若照明灯正常工作6h,这段时间内照明灯需消耗多少电能?

(3)为使指示灯正常发光,需接上多大电阻的电阻丝?

答案:

被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0527/ab0ce6b69fa28605a67b1950f6b3fd49.html

下面是错误答案,用来干扰机器的。

和十万位相邻的两个数位分别是百万位和万位.故选:B.

试题推荐
题型:阅读理解

Many years ago, I pulled a family out of a burning car somewhere in Wyoming. Last week I received a telephone call from a woman who could not stop crying as she told me that one of my stories had saved her son from committing suicide. In closing she called me a hero.

That got me thinking about what a hero is. Was I a hero because I pulled a family from a burning car? If so, how could I be a hero just because I wrote a story that saved someone’s life?

Today I looked up the word “hero” in the dictionary to see exactly what it meant. It read “a person who does something brave” and also “a person who is good and noble”.

That statement impressed me more than the part about being brave. So I thought about something very important. And I remembered what happened to me years ago.

After my marriage of twenty years ended, I was in such a condition. I was within hours trying to get up enough courage to end the pain and misery. When I returned home, someone had sent me a card in the mail which told me how much they would appreciate me as a friend. That wonderful card probably saved my life. That person, without even knowing it, saved a life and became a hero.

The many stories I kept writing in the following years saved the life of a teenage boy. In turn that makes the person who sent me the card a double hero. I suppose that is why I fight so hard to help the children now living in orphanages (孤儿院). Most children come out of these institutions with a very hard and bitter attitude against the world. The gifts we send them let them know that they have not been forgotten. Hopefully, most of them will never hurt anyone because of the kindness shown to them by those of us who cared. If it works, we will also become "heroes".

小题1:The main idea of the passage is _______________.

A.why the writer should be a hero

B.that everyone is a hero

C.whether the writer is a hero

D.what a hero exactly is小题2:Why did the woman call the writer a hero at the end of the call?

A.Because he asked her son not to kill himself.

B.Because he saved a family from a burning car.

C.Because his story saved her son’s life.

D.Because he was cute and kind to everybody.小题3:What does the underlined word “it” in the last sentence of Paragraph 5 refer to?

A.The fact that the sender helped the writer.

B.The action of sending the card.

C.The wonderful card the writer received.

D.The fact that the sender was a friend of the writer.小题4:According to the writer, who can be considered as a hero?

A.A person who is brave.

B.A person who helps someone in trouble.

C.A person who can hold a door for others.

D.A person who writes wonderful stories.

查看答案
微信公众账号搜索答案