Now the role played by knots in fundamental physics seems so important that we might even guess that the reason space has three dimensions is that it is the only number of dimensions within which you can tie knots in strings.

— Event-Symmetric Space-Time

— P. Gibbs

2010.07.07 Wednesday ACHK


Wave velocity

這段改篇自 2010 年 3 月 18 日的對話。

波動速度(wave velocity)的公式是:

v 是 wave velocity(波速);

f 是 frequency(頻率);而

是 wavelength(波長)。


(1) Wave velocity ,v,只是同介質(medium)有關。即是對於同一種 wave 來說,同一種 medium,就會有同一個 wave velocity。[1]

(2) Frequency,f,只是同波源(wave source)有關。即是 source 的 frequency 是多少,那個 wave 的 frequency 就是多少[2],無論該個 wave 中途跨個多少個山,越過多少個海。

— Me@2010.07.07

[1] 這句只適用於中學程度的物理學(HKCEE/HKAL/HKDSE physics)。

[2] 為什麼呢?

2010.07.07 Wednesday (c) All rights reserved by ACHK