ispeakmath
•
New Member
Posts: 3
Likes: 0
Gender: Male
|
Post by ispeakmath on May 1, 2016 1:28:18 GMT
If the energy of an EM wave is related to its amplitude only, why do they teach us that longer wavelength = less energy?
|
|
|
|
Post by Vincent on May 1, 2016 1:59:44 GMT
If the energy of an EM wave is related to its amplitude only, why do they teach us that longer wavelength = less energy?
That's a very interesting question that confuses a lot of people. If you take an entire EM wave, the energy is indeed proportional to the square of the amplitude and independent of the frequency or wavelength. However, due to quantum mechanics, we know that electromagnetic waves are quantized, or that there is a "smallest unit" of the wave, the photon. The misconception comes from the fact that, for a single photon, the energy is directly proportional to the frequency (E=hf) and the amplitude is calculated from the frequency. This also gives the result that, if you somehow took a certain number of photons at a low frequency and somehow accelerated them to a high frequency, the amplitude of the whole wave would increase proportionally to the square of the frequency.
tl;dr whole wave ->E proportional to A2, single photon ->E proportional to f
Hope this helps!
Also, moved to new thread (not a resource). |
|
