Question

lasers: the light fantastic!
1 since the early days of ancient greece, egypt, rome, china, and india, rays of light have been thought to possess mysterious, even magical powers. the ancients believed light could carry messages from the gods and that the sun was responsible for imbuing life. light, they believed, could even cure serious illnesses.

1. ordinary light is comprised of many light rays of different wavelengths, all out of step with each other. thats why most visible light diffuses, or spreads out, from its source. you probably have experienced this if you have ever been in a darkened room and lit a candle or turned on a small light bulb. the light, in these examples, is brightest at its source. as it moves away from its point of origin, the light covers more area but it grows dimmer. people wondered if there was any way to keep the intensity of light the same as it is at its source?
2. use lasers: the light fantastic! to answer the following question:

the author includes paragraph 2 to

• argue the benefits of light
• explain why a laser is such a useful tool
• address the reason why lasers were invented
• suggest that more research should be done on light rays

Explanation:

To determine the purpose of paragraph 2, we analyze its content. Paragraph 2 describes ordinary light's properties (multiple wavelengths, out of step, diffuses) and poses a question about keeping light intensity constant. This relates to why lasers (which have coherent, focused light) are useful. The first option is incorrect as the paragraph isn't about light's benefits. The third option is wrong as it doesn't address laser invention reasons. The fourth option is incorrect as it doesn't suggest more research on light rays. The second option fits as explaining ordinary light's limitations sets up why lasers (with consistent intensity) are useful tools.

Answer:

B. explain why a laser is such a useful tool