问题 问答题

如图为圆盘发电机的示意图,铜盘绕水平的铜轴C在垂直于盘面的匀强磁场中转动,铜片D与铜盘的边缘接触,铜盘、导线和电阻R连接组成电路,则(  )

A.转动过程电能转化为机械能

B.C处的电势比D处高

C.通过R的电流方向从B向A

D.产生的电动势大小与角速度ω无关

答案

A、圆盘在外力作用下切割磁感线,从而产生感应电动势,出现感应电流,因此转动过程中将机械能转化为电能,故A错误;

B、根据右手定则可知,电流从D点流出,流向B点,因此电流方向为从B向A,由于圆盘在切割磁感线,相当于电源,所以C处的电势比D处低,故B错误,C正确;

D、根据法拉第电磁感应定律,则有E=BLV=

1
2
BL2ω,所以产生的电动势大小与角速度ω有关,故D错误;

故选C

阅读理解

Australia’s Northern Territory became the first legal authority in the world to perform euthanasia(安乐死)—that’s to say, doctors are permitted to take the lives of incurably ill patients who wish to die. Word that the law was passed by the vote of 15 to 10 immediately flashed on the Internet and was picked up by John, the director of the Right to Die Society of Canada, who posted it on the group’s homepage online, saying, “This isn’t merely something that happened in Australia. It’s world history.”

The NT Rights of the Terminally Ill Law has left physicians and citizens trying to deal with its moral and practical influence. Some have breathed sighs of relief; but others, including churches, right to life groups and the Australian Medical Association, bitterly attacked the law. But the tide is unlikely to turn back. In Australia--where an aging population, life-extending technology and changing community attitudes have all played their part—other states are going to consider making a similar law. In the U. S. and Canada, where the right to die movement is gathering strength, observers are waiting for the dominoes (多米诺骨牌) to start falling.

Under the new Northern Territory law, an adult patient can request death--probably by a deadly injection or pill--to end suffering. The patient must be diagnosed as incurably ill by two doctors. After a "cooling off" period of seven days, the patient can sign a certificate of request. After 48 hours the wish for death can be met. For Lloyd, a 54-year-old Darwin resident suffering from lung cancer, the NT Rights of Terminally Ill Law means he can get on with living without the disturbing fear of his suffering: a terrifying death from his breathing condition. "I' m not afraid of dying from a spiritual point of view, but what I was afraid of was how I'd go, because I've watched people die in the hospital fighting for oxygen and clawing at their masks," he says.

小题1:According to the text, which of the following statements is TURE?

A.Patients will ask their doctors for euthanasia if they are afraid of illness.

B.Australia, Canada and the US speak highly of the law of euthanasia.

C.All people in Australia don’t share the positive attitude to euthanasia

D.If a patient requests death, he should sign a certificate after 48 hours.小题2:The underlined sentence in Para 2, “observers are waiting for the dominoes to start falling.” means that observers are prepared to learn the news that         .

A.some other countries pass similar laws

B.Australia has to put an end to euthanasia

C.people begin to change attitudes to euthanasia

D.different effects result from the game of dominoes小题3:Which is NOT the reason for Australia to become the first country to pass the law of euthanasia?

A.Australia has advanced technology of extending life.

B. Australians realize suffering from a terrible disease is worse than death.

C.Australia is faced with a growing ageing population.

D.Australians find it easy to deal with the moral and practical influence.小题4:It can be inferred from the text that          .

A.Australia passed the law of euthanasia by the vote of 15 to 10

B.John and his group are in favor of the law of euthanasia in Australia.

C.an adult patient can request euthanasia by a deadly injection or pill

D.Lloyd has seen many people die in the hospital fighting for oxygen.小题5:What’s the author’s attitude to euthanasia?

A.Negative

B.Critical

C.Doubtful

D.Positive

单项选择题