Wavelengths can be determined of photons by color, do photons have wave amplitudesand how are they measured?

Question

Wavelengths can be determined of photons by color, do photons have wave amplitudesand how are they measured?

Answer 1

A good question. The intensity of a beam of light is determined by the number of photons and its colour by the wavelengths of the photons. All photons of a particular frequency have the same energy, equal to the frequency times Planck's constant, or equivalently equal to Planck's constant times the speed of light divided by the wavelength. Einstein's photoelectric effect experiment proved this, and earned him a Nobel prize. So all photons of a particular colour have the same amplitude.

Answer 2

colour straight away corresponds to frequency in the wave type, or power in line with photon in the particle type. those characteristics also ensure spectral area. Spectral areas are literally labeled in step with human adventure and technologies. do not enable every person allow you to recognize wavelength specifies colour. Wavelength transformations at the same time as mild transformations media of diverse refractive indexes.

Answer 3

This is a very interesting question, and to give it the full treatment it deserves one would need to tread well outside the scope of a Yahoo answers response (i.e. it would be very heavy on quantum field theory & quantum mechanics, etc.).



What might help is to consider what physicists call the "Poynting vector", which gives you the energy flux of the wave (i.e. the power transmitted per unit area).



The magnitude of the Poynting vector is E^2/(c*mu_0), where c is the speed of light and mu_0 is the permeability of free space. Averaging over the sinusoidal wave gives an average energy flux of E_0^2/(2*c*mu_0)



The average energy flux is also equal to (hf) times the average photon flux.



So you have an expression for the electric field amplitude in terms of the photon flux and the frequency of the light.



But what is the photon flux of a single photon? Remember, the photon flux is the number of photons per unit time, per unit area. This is precisely where it starts to get confusing. At the very least you need to throw out the assumption that the electric field is an infinite periodic plane wave, because both the "infinite periodic" and the "plane wave" part give an electric field of zero for a finite photon energy.



All that really needs to be said is that if you're measuring the electric field, you're not particularly interested in the electric field of each photon because you're only measuring the total electric field. If you want the energy (and hence frequency) of a single photon, you never deal with the electric field amplitude directly, just the integral of its square over time and space.