Snell's law點樣證明

[S]【YU】

According to Physics Beyond 2000




p/s: From wikepedia, refractive index is proportional to wave speed

The refractive index, n, of a medium is defined as the ratio of the velocity, c, of a wave phenomenon such as light or sound in a reference medium to the phase velocity, vp in the medium itself:

andykwok123321

physics真係深,,(汗

adamsteve

花花  YU爺實岩架   大師兄黎架

一係我換過一個講法比你聽
咁唔同介質  光速都有唔同
例如 玻璃出空氣 係咪會快左先

咁你當佢好似架車咁   你當條光線有粗幼啦
我計佢偏左45度射出     咁係咪好似架車 左碌出先 右碌後出
咁一出左去  就會快左呀ma   咁所以  左邊行得快過右邊   就會轉左啦!!!
e個就係最基本原理  你記得佢係咁 之後背返yu爺比你ge proof就可以架啦

[S]【YU】

我唔係實啱既,不過textbook照dup出黎,無咁易錯je.
車輪解法只可以解釋點折法,至於數學上證明 n1sin$1 = n2sin$2 ,就要用上面堆野.

櫻花之臣

花花  YU爺實岩架   大師兄黎架

一係我換過一個講法比你聽
咁唔同介質  光速都有唔同
例如 玻璃出空氣 係咪會快左先

咁你當佢好似架車咁   你當條光線有粗幼啦
我計佢偏左45度射出     咁係咪好似架車 左碌出先 右 ...
adamsteve 發表於 14-10-2009 00:53

喔0,0" 我都覺..

我對理科完全唔理解-,-"

eddypoon

A wave is travelling from region 1 to region 2
Let A be the point which first undergoes refraction,
     B the point last,
Assume that the time taken for B to undergo refraction after A is t, v1 the velocity of the wave in region 1, v2 in region 2.
BB' = v1 * t
AA' = v2 * t
BB' / sin(a1) = B'A = AA' / sin (a2)
i.e v1 * t / sin(a1) = v2 * t / sin (a2)
Simplifying, v1 / v2 = sin (a1) / sin (a2)
For constant frequency f, using v = f入
入1/ 入2 = v1 / v2 = sin (a1) / sin (a2)