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发布时间:2014-04-17 14:21:52  


Passage 1 total: 148 words spontaneous while stimulated emission is different because it occurs when an atom or molecule is stimulated to send off lights. was not until after the Second World War that physicists began to seek ways by which one atom or molecule could be stimulated to emit light, amplifying it too much higher powers.

The key concepts emerged in 1957. Towness and Artyur Schawlow, wrote a long paper summerizing the conditions required to amplify stimulated emission of visible light waves. Meanwhile, similar ideas crystallized in the mind of Gordon Gould, then a 37-year-old graduate student at Columbia, who wrote them down in a series of notebooks.



1. The word “it” (line 2) refers to______.

A) stimulated emission B) energy C) molecule D) atom

2. A laser can be best illustrated as ______.

A) a phenomenon of stimulating atoms and molecules to give off light

B) an atom in a highenergy status

C) a technique for destroying atom or molecules

D) an instrument for measuring light waves

3.When did scientists attempted to search for ways by which an atom could be stimulated to give off light?

A) before the second world war broke out.

B) when the second world war was at its peak.

C) when the second world war came to an end.

D) when laser technique had already been fully developed.

4.In his research at Columbia University Charles Towness worked with all of the following EXCEPT______.

A) stimulation B) amplification C) invisible lights D) conditions to emit lights

5. It can be concluded from the passage that ______.

A. Towness and Artyur Schawlow worked in the same institute

B. Gordon Gould’s concept was different from that of Towness

C. The breakthrough didn’t came into being until 1957 although much had been done on laser


D. Towness varies in views from other two scientists




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