[audioFiles]audio_ezfm_0106(20104)[/audioFiles]

游客2023-11-19 46

问题

选项

答案                                           Laser
   A laser is used to produce very powerful beams of light./Today laser is getting wider use in more fields./ Why is laser so much more powerful than other kinds of light? /
   Laser is a kind of light and also a form of energy./A laser beam is made up of very short waves . /These waves all have the same wavelength. /The laser beam keeps going on and off all the time./As these changes are very fast, we can but see them./During the time the laser beam is off,/the energy for the next burst of light is being built up,/so when the beam is on again, it will be a strong burst./And the laser beam doesn’t spread,/it doesn’t get wider and wider as other fight beams do./This is why the laser beam can keep all of its energy/and is so much more powerful than other light beams.

解析

转载请注明原文地址:https://www.tihaiku.com/zcyy/3200412.html

相关试题推荐

随机试题

最新回复(0)

[audioFiles]audio_ezfm_0106(20104)[/audioFiles]

[audioFiles]audio_ezfm_0001(20104)[/audioFiles]Adogisthemostusefulan

[audioFiles]audio_ezfm_0277(20104)[/audioFiles]