劍橋詞典the fact of light or sound being caused to change direction or to separate when it travels through water , glass , etc. 折射 ?absolute index of refraction a calculation of the relationship between the speed of light moving through a medium (= substance ) and the speed of light in a vacuum (= an area with no matter in it) 絕對(duì)折射率 ?angle of refraction the angle that a beam of light or other energy that is refracted by a surface makes with a line vertical to that surface 折射角 返回 refraction