Photons, as particles of light, do have wavelengths and frequencies. In fact, the wavelength and frequency of a photon are directly related to each other through the speed of light in a vacuum, which is a fundamental constant denoted by 'c'.
The relationship between the wavelength (λ), frequency (f), and speed of light (c) is given by the equation:
c = λf
By rearranging this equation, we can determine the frequency of a photon:
f = c / λ
Similarly, we can determine the energy of a photon using Planck's equation, which relates the energy (E) of a photon to its frequency:
E = hf
Here, 'h' represents Planck's constant, which is another fundamental constant. Thus, the energy of a photon is directly proportional to its frequency.
By combining these equations, we can express the energy of a photon in terms of its wavelength:
E = hc / λ
Therefore, while photons are massless particles and do not possess a classical wavelength in the same way as sound waves, they do have a well-defined wavelength and frequency that are interconnected through the speed of light. This allows us to calculate their frequency and energy using the equations mentioned above.