如图所示,在竖直向下的磁感应强度为B的匀强磁场中,金属框架ABCD固定在水平面内

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问题:

如图所示,在竖直向下的磁感应强度为B的匀强磁场中,金属框架ABCD固定在水平面内,AB与CD平行且足够长,BC与CD夹角,光滑导体棒EF(垂直于CD)在外力作用下以垂直于自身的速度v向右匀速运动,框架中的BC部分与导体棒在滑动过程中始终保持与导轨良好接触,光滑导体棒EF经过C点瞬间作为计时起点。若金属框架与导体棒是由粗细相同的均匀的同种材料组成的导体,下列关于电路中电流大小I与时间t、消耗的电功率P与导体棒水平移动的距离x变化规律的图象中正确的是

[ ]

A.

B.

C.

D.

考点:电磁感应现象中的切割类问题
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B Customs of Bulgaria: Marriage and Family保加利亚习俗:婚姻与家庭
The average age for women to marry is between 18 and 25.25 tend to (1) when somewhat older. A church wedding often (2) the legal civil ceremony, and a large reception, which often involves (3) music and dancing, is held in the evening. Wedding traditions include (4) money on the bride’s dress to represent future prosperity, the groom (5) the bride at her home, and the couple pulling on opposite (6) of a loaf of bread—whoever gets the largest piece will be (7) boss of the family. Honeymoons are a new tradition.
The principle (8) mutual support is valued in the Bulgarian family. The elderly are (9) cared for by their adult children. Unmarried adults live with their (10) and many newly married couples live with one set of parents (11) they are able to get housing of their own. Most families (12) urban areas live in apartments, which are in short
supply, while (13) in rural areas usually have their own houses. Many village houses (14) owned by families who live in urban areas, who use them_ (15) summer and weekend retreats, or for retired parents.
Most families in (16) areas do not have more than two children, while families in (17) areas tend to be larger. Grandparents play an important role in (18) care, particularly in urban areas, where most women work outside the (19) . Men of the younger generation have begun to help with household (20) , once considered only women’s responsibility.

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管道内壁底到地面的距离称为( )。

A.最小覆土厚度

B.最大允许埋深

C.覆土厚度

D.埋设深度

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男性,21岁,因饱餐后活动,突感中腹部剧烈疼痛,阵发加重,伴呕吐,未排气、排便,查体:腹部隆起,压痛明显,肠鸣音亢进。

下一步检查方法是()

A.血尿淀粉酶检查

B.上消化道钡餐造影

C.腹部立位平片

D.B超检查

E.血管造影

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使起搏阈值降低的情况是()。

A.心肌缺血、坏死、纤维化

B.电极与心肌的距离增加

C.脉宽变窄

D.低钾血症

E.睡眠状态

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非团队游客的送站服务,导游员的主要工作有()。

A、详细阅读送站计划

B、做好送站准备

C、到饭店接运客人

D、到站送别

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