题干

如图甲是法拉第圆盘发电机实物图,主要部分是一个在磁场中转动的导体圆盘.若磁感线方向如乙图所示,导体圆盘绕中心轴按逆时针方向转动,当A、O分别与电路中的C、D接通时,设流过灯的电流为I1;当A、B分别与电路中的C、D接通时,设流过灯的电流为I2。则(  )

A:I1为零,I2为零

B:I1不为零,I2为零

C:I1为零,I2不为零

D:I1不为零,I2不为零

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答案(点此获取答案解析)

B

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阅读下面短文,根据文章大意用所给单词的适当形式填空(未提供单词的,限填一词),使文章意思完整、正确。

    Everything about me elephant is big, from its size to how long it takes for a baby elephant to be born. Of all land animals, the elephants have the ____ (large) brain and can talk to each other using their own language. They also have ____ very good memory. They can remember lots of other elephants that they have known and have friends and family the same way humans do. They will get very sad ____ one dies and they help family members when they are sick or hurt.

    In India and Africa they ____ (use) for transportation and to carry tourists around animal parks. Elephants are different ____ many other animals because they are very kind and care about humans. They are gentle and kind and don't hurt anyone. They will only fight to protect ____ (they). There is a story of an ____ (India) king who died and for over 30 years his favourite elephant was very sad and would not do anything.

    And how do we humans treat elephants? For ____ (thousand) of years elephants have been treated very ____ (bad) and killed by humans. Although there is an international agreement to stop the ivory (象牙) from being sold, people still shoot and kill elephants to get their tusks. In fact, in 20 years there might not be any elephant left on Earth. So it is important for us ____ (save) the elephants before it's too late.