根据玻尔理论，氢原子在n=5轨道上的角动量与第一激发态的轨道角动量之比为
A. 5/2
B. 5/3
C. 5/4
D. 5
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具有下列哪一个能量的光子，能被处在n=2的能级的氢原子吸收？
A. 1.51eV
B. 1.89eV
C. 2.15eV
D. 2.40eV
使氢原子中电子从n=3的状态电离，至少需要供给的能量为[ C ](已知基态氢原子的电离能为13.6eV)
A. -12.1eV
B. 12.1eV
C. 1.51eV
D. -1.51eV
Which of the following statements about news is true?
A. News is truthful reflection of fact.
B. News is accurate information without subjective elements.
C. News is a product of construction.
D. News is constructed with no bias or personal values involved.
What element on media may be a representation?
A. a person
B. a country
C. an event
D. all of the above.
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