搜题请搜索小程序“爱下问搜题”
问题 选择题

如图所示为氢原子的能级图．用光子能量为13.06 eV的光照射一群处于基态的氢原子，可能观测到氢原子发射的不同波长的光有：   

A．6种

B．10种

C．12种

D．15种

答案

答案：B

用光子能量为13.06 eV的光照射一群处于基态的氢原子，原子可以跃迁到n=5的能级，可能观测到氢原子发射的不同波长的光有4+3+2+1=10种，B对；

改错题

文中共有10处语言错误，每句中最多有两处，每处错误仅涉及一个单词的增加、删除或修改。增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。删除：把多余的词用斜线（\）划掉。修改：在错的词下划一横线，并在该词下面写出修改后的词。注意：1.每处错误及其修改均限一词。2.只允许修改10处，多者（从第11处起）不计分。

This morning I went to ask for my English teacher to give me some advice on why to learn English well on the weekend. When I arrived his office at 8 o’clock, he had already done her work for almost one hour. First, we should make a plan of study and carry them out until we succeed. Then, we must master any basic knowledge of English such as 26 letters and 48 sounds. Vocabulary is bricks and grammar is bones. We can make different kinds of phrases and sentences with them according the rules. Finally, practice make perfect. When I leave, it was 12 o’clock. Through this lesson, I learned something which couldn’t be learned from textbooks. 
查看答案
选择题

对于100mL 1mol/L盐酸与锌粒的反应，采取下列措施能使放出H2速率加快的是

①升高温度

②改用100mL 1mol/L硫酸

③多用300mL 1mol/L盐酸；

④用等量锌粉代替锌粒

⑤改用100mL 6mol/L硝酸

⑥滴入几滴硫酸铜溶液

⑦用粗锌代替纯锌使用

A．①③④⑤⑦

B．①②④⑥⑦

C．②③④⑤⑥

D．①②③⑥⑦
查看答案