如图所示,金属板放在垂直于它的匀强磁场中,当金属板中有电流通过时,在金属板的上表

题型:选择题

问题:

如图所示,金属板放在垂直于它的匀强磁场中,当金属板中有电流通过时,在金属板的上表面A和下表面A′之间会出现电势差,这种现象称为霍尔效应。若匀强磁场的磁感应强度为B,金属板宽度为h、厚度为d,通有电流I,稳定状态时,上、下表面之间的电势差大小为U。则下列说法中正确的是(  )

A.在上、下表面形成电势差的过程中,电子受到的洛仑兹力方向向下

B.达到稳定状态时,金属板上表面A的电势高于下表面A′的电势

C.只将金属板的厚度d减小为原来的一半,则上、下表面之间的电势差大小变为U/2

D.只将电流I减小为原来的一半,则上、下表面之间的电势差大小变为U/2

考点:磁场对运动电荷的作用:洛伦兹力、左手定则
题型:选择题

试油过程中,井口装好压力表,主要记录油压。

题型:选择题

An Israeli law banning too skinny models went into effect with the start of 2013. The law, approved last March in Israel, requires models to prove they have maintained a Body Mass Index (BMI) of at least 18.5 for three months before a fashion show. That means a woman who is 5'8'' tall can weigh no less than 119 pounds.

“This law is another step in the war against eating disorders,” said physician Adatto. “Underweight models,” he explained, “can no longer serve as role models for innocent young people who copy their false image of being skinny.”

But some critics in this country say it is misguided, focusing on weight instead of health. They also say the Israeli ban is bound to fail because of the strong power of the fashion industry. “I think it’s an approach that isn’t going to work.” Said eating disorder expert Susan Ice, who worked with an organization which creates a healthy working environment for models.

But Adatto told the reporter that he began to concern the issue after meeting an ambitious model who looked like she needed to be hospitalized. He said. “I realized that only legislation can change the situation. There was no time to waste, so many girls were dieting to death.”

However, the efforts to regulate models’ weight in Spain and Italy have not resulted in significant changes in part because of difficulties in determining reliable methods of measuring weight and health.

Still, folks including Ice say there’s no denying that images from Hollywood and the fashion industry can be difficult for young women to deal with. “Certainly I don't believe the modeling industry has caused the rise in eating disorders, but it makes it harder,” she says. “It’s a difficult recovery environment, worshiping thinness as the beauty ideal.”

小题1:What does BMI in the first paragraph refer to?

A.A new show held by those skinny models.

B.A worldwide prize for the healthiest model.

C.A measure of body health based on height and weight.

D.A kind of medicine to cure eating disorders.小题2:One benefit the new Israeli law may bring is ________.

A.to change the working conditions of models

B.to prevent models from suffering from eating disorders

C.to lower the chance of skinny models’ death

D.to provide guidance for women worshiping thinness小题3:In the opinion of the critics, the law won’t succeed because         .

A.the fashion industry is much too influential

B.it misleads young women to form a bad eating habit

C.it doesn’t provide a proper approach that can work well

D.it doesn’t create a healthy working environment for models小题4:According to the passage, the new Israeli law banning skinny models is         .

A.practical

B.acceptable

C.reasonable

D.controversial

题型:选择题

依据《中国人民银行假币收缴、鉴定管理办法》规定,中国人民银行可对金融机构()行为给予警告、罚款,同时,责成金融机构对相关主管人员和其他直接责任人给予相应纪律处分。

A.发现假币而不收缴的

B.未按照《中国人民银行假币收缴、鉴定管理办法》规定程序收缴假币的

C.发现假币应向人民银行和公安机关报告而不报告的

D.截留或私自处理收缴的假币,或使已收缴的假币重新流入市场的

题型:选择题

关于小龙虾,以下说法错误的是?()

A.购买小龙虾时要挑选背部红亮干净的

B.野生小龙虾比养殖小龙虾更安全

C.不要食用小龙虾的头部

D.小龙虾的消化道——虾线是重金属污染和病菌污染较为严重的地方

题型:选择题

JIT这个概念意味着:()。

A、零缺陷

B、零库存

C、100%检验

D、属性抽样

更多题库