rad
 |
以平面角為例 r θ = s θ = s /
r s和r的因次都是m所以θ 無因次 |
k
 |
k = 2π / λ ① 因為rad沒有因次 波數的因次是m-1 |
f
 |
| f = c / λ ② 感覺是光走1秒有幾個波 |
ω
 |
| 2π f = ω |
k c = ω
 |
| k c = ω |
我知道了從波數出發 🤔
k = 2π / λ ①
f = c / λ
f / c = 1 / λ
f / c = 1 / λ
put into ① then get
k = 2π f / c
k c = 2π f
finally
k c = 2π f = ω
這樣不是更簡單 🤠
f = c / λ ②
2π f = 2π c / λ
ω = k c
