如图所示,由电源、定值电阻和滑动变阻器构成一闭合电路,一粒子加速枪并接在两端,在

题型:问答题

问题:

如图所示,由电源、定值电阻和滑动变阻器构成一闭合电路,一粒子加速枪并接在两端,在加速枪口正上方处的点真空区域有一固定的点电荷,带电量为。现有质量和带电量均不同的两种带负电静止粒子,从加速枪的左端加速后从点进入场区域,粒子射入枪口时速度方向垂直于连线。

(1)试证明若加速电压满足一定条件,两种粒子在场区域都能做匀速圆周运动。(不计粒子的重力)

(2)当滑动变阻器滑动头在某位置时,射出的带电粒子恰好做匀速圆周运动,若将向左移动一小段距离后,该种粒子从加速枪中射出后的运轨迹变成什么形状?它的周期比圆周运动时长还是短?(只写明最后结论)

考点:库仑定律
题型:问答题

关于建设工程项目信息编码的方法,正确的解释是______。

A.项目的投资项编码应按概预算定额确定的分部分项工程的编码

B.项目的进度编码应综合考虑不同层次、不同深度和不同用途的进度计划工作项的需要,建立统一的编码

C.同一项目不同参与单位必须采用同一套编码

D.项目进展报告和各类报表编码应包括项目管理形成的各种报告和报表的编码

E.函件编码应反映发函者、收函者、函件内容所涉及的分类和时间

题型:问答题

孟塞尔色标N4/颜色的明度为()。

A.N4

B.N

C.4

D./

题型:问答题

根据《药品经营质量管理规范》,下列关于药品批发企业出库管理的叙述,错误的是

A.药品出库应进行复核和质量检查
B.药品出库应遵循“先产先出”、“近期先出”和按批号发货的原则
C.第一类精神药品和第二类精神药品应建立双人核对制度
D.药品出库应做好药品质量跟踪记录
E.质量跟踪记录应保存至超过药品有效期1年,但不得少于3年

题型:问答题

German Chancellor Angela Merkel won over German voters in the Federal Election on Sept. 27. Can she now be won over by a French charm offensive (1) at repairing the relationship that was once at the heart of Europe That’s the question being asked in Paris, (2) top government officials are (3) talking about their desire to rekindle closer ties (4) their neighbors across the Rhine. (5) the end of World War II the Franco-German relationship has been the motor of European integration, the (6) force behind the creation of the European Union and, more recently, the introduction of the euro. But the ardor has (7) in this decade, particularly under Merkel, who has regularly struggled to (8) her irritation with French President Nicolas Sarkozy’s grandstanding. Sarkozy, (9) , has often been impatient with what he (10) Merkel’s lack of resolve.

The sometimes (11) personal rapport is a long way from the public shows of affection their predecessors staged, particularly Helmut Kohl and FranCois Mitterrand, who movingly held (12) in 1984 in a Verdun cemetery. There’s been tension on (13) , too. Charles Grant, director of the London-based think tank Centre for European Reform, points out that France and Germany have been (14) on issues from how best to reflate their economies during the economic (15) to the smartest strategies for dealing with Russia.

But influential movers in France are now (16) to put the relationship back on a friendlier footing. In a recent paper French think tank Institute Montaigne (17) an ambitious agenda for the two nations, (18) that a new impetus is needed if Europe’s voice is to be heard in a world (19) of big new players, such as Brazil and India, and at a time when President Obama seems fax more (20) with China and the rest of Asia than with America’s traditional allies in Europe.

5()

A.Since

B.Before

C.At

D.For

题型:问答题

高层建筑供电负荷中,客用电梯供水系统公用照明属于()

A.一级负荷

B.二级负荷

C.三级负荷

D.四级负荷

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