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问题 选择题

如图所示是氢原子的能级图．若一群处于n=3激发态的氢原子跃迁到n=2激发态时发射出的是红光，则这群处于n=3激发态的氢原子发生跃迁还可能发射出（　　）

A．红外线

B．紫外线

C．β射线

D．γ射线

答案

处于n=3激发态的氢原子发生跃迁，根据

C2n
得能发射出3种频率的光．

处于n=3激发态的氢原子跃迁到n=2激发态时发射出的是红光，

根据hγ=Em-En，其他两种光的频率大于红光的频率，即紫外线．

故选B．

单项选择题

When you are (71) a home or small office network, it is recommended that you use the Network Setup Wizard in Windows XP Home Edition to enable Internet Connection Sharing. The Network Setup Wizard automatically provides all of the network settings you need to (72) one Internet connection with all the computers in your network.
After ICS is enabled, and you make sure that all of your computers can (73) with each other and they have Internet (74) , you can use programs such as Internet Explorer and Outlook Express as if they were (75) connected to the Internet service provider (ISP). When a request to the Internet is made, the ICS host computer connects to the ISP and creates the connection so that other computers can reach a specified Web address or download E-mail.

A．communicate

B．communications

C．correspond

D．correspondence
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单项选择题

影响焊接变形的因素是很多的，但对于生产工人来说是（）。

A、焊件的加热程度

B、焊接顺序

C、装配顺序

D、以上三者都是
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