(A) The word 'laser' was coined as an acronym for 'Light Amplification by the Stimulated Emission of Radiation'. Ordinary light, from the Sun or a light bulb, is emitted spontaneously when atoms or molecules get rid of excess energy by themselves, without any outside intervention. Stimulated emission is different emit it as light when an atom or molecule holding onto excess energy has been stimulated to emit it as light.
Albert Einstein was the first to suggest the existence of stimulated emission in a paper published in 1917. However, for many years, physicists thought that atoms and molecules were always much more likely to emit light spontaneously and that stimulated emission thus would always be much weaker. It was not until after the Second World War that physicists began trying to make stimulated emission dominate. They sought ways by which one atom or molecule could stimulate many others to emit light, amplifying it to much higher powers.
The first to succeed was Charles H. Townes, then at Columbia University in New York. Instead of working with light, however, he worked with microwaves, which have a much longer wavelength, and built a device he called a "maser" for Microwave Amplification by the Stimulated Emission of Radiation. Although he conceived the key idea in 1951, the first maser was not completed until a few years later. Before long, many other physicists were building masers and trying to discover how to produce stimulated emission at even shorter wavelengths.
(B) The key concepts emerged about 1957. Townes and Arthur Schawlow, then at Bell Telephone Laboratories, wrote a long paper outlining the conditions needed to amplify stimulated emission of visible light waves. At around the same time, similar ideas crystallized in the mind of Gordon Gould, then a 37-year-old graduate student at Columbia, who documented them in a series of notebooks. Townes and Schawlow published their ideas in a scientific journal, Physical Review Letters, but Gould filed a patent application. Even three decades later, the debate continues over who deserves credit for the invention of the laser.
1. The word "coined" in paragraph (A) could best be replaced by?
2. The word "intervention" in paragraph (A) can best be replaced by?
3. The word "it" in paragraph (A) refers to?
4. Which of the following statements best describes a laser?
5. Why was Towne's early work with stimulated emission done with microwaves?
6. In his research at Columbia University, Charles Townes worked with all of the following EXCEPT?
7. In approximately what year was the first maser built?
8. The word "emerged" in paragraph (B) is closest in meaning to?
9. The word "outlining" in paragraph (B) is closest in meaning to?
10. Why do people still argue about who deserves the credit for the concept of the laser?