题干

小明同学在物理实践活动中,设计了如图所示的反映弹簧所受压力大小的电路,其中R′是标有“1A 20Ω”滑动变阻器,R是5Ω定值电阻,电源两极间电压恒定为10V,下列说法错误的是(  )

A:滑片受到压力增大时,变阻器阻值增大

B:当压力最大时,电路中的电流为0.4A

C:压力最大时,定值电阻R两端的电压为0

D:压力表实际是电压表

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C

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七选五

          What is your favorite color? Do you like yellow, orange, red? (1)____ Do you prefer grey and blue? Then you are probably quiet, shy, and you would rather follow than lead.  You tend to be a pessimist(悲观者).  At least, this is what psychologists(心理学家)tell us, and they should know, because they have been seriously studying the meaning of color preference, as well as the effect that colors have on human beings. (2)____If you happen to love brown, you did so, as soon as you opened your eyes, or at least as soon as you could see clearly. (3)____A yellow room makes most people feel more cheerful and more relaxed than a dark green one; and a red dress brings warmth and cheer to the saddest winter day. (4)____A black bridge over the Thames River, near London, used to be the scene of more suicides(自杀者)than any other bridge in the area—until it was repainted green.  The number of suicide attempts immediately fell sharply.  Perhaps it would have fallen even more if the bridge had been done in pink or baby blue. (5)____It is an established fact(既成的事实)that factory workers work better, harder, and have fewer accidents when their machines are painted orange rather than black or grey.

    A. On the other hand, black is depressing.

    B. They tell us, among other facts, that we do not choose our favorite color as we grow up—we are born with our preference.

    C. The rooms are painted in different colors as you like.

    D. If you do, you must be an optimist, a leader, an active person who enjoys life, people and excitement.

    E. Light and bright colors mak e people not only happier but more active.

    F. Life is like a picture or a poem, full of different colors.

    G. Colors do influence our moods—there is no doubt about it.