# Do all the photons have the same energy? [duplicate]

The title is pretty self-explanatory. Do all the photons have the same energy?

• ASCII I Imagine that you are young and that is why a gave you an up. Commented Feb 24, 2017 at 16:51
• No. Photons with smaller wavelength have higher energy. The relation between them is given by the Planck constant. You can read more from that in this question. Commented Feb 24, 2017 at 17:09
• Possible duplicate of Can someone explain Planck's constant simply? Commented Feb 24, 2017 at 17:10
• I'm voting to close this question because a simple google search would have given the answer. Commented Feb 24, 2017 at 17:38
• -1. No research effort. Commented Feb 25, 2017 at 3:24

No, the energy of a photon is connected to its frequency $\nu$ via $$E = h\nu$$ where $h$ is the Planck constant. So a blue photon is more energetic than a red one, for example.

• But how does a single photon have a frequency. Commented Feb 24, 2017 at 15:17
• @ASCII This was answered here: physics.stackexchange.com/questions/29010/… Commented Feb 24, 2017 at 15:19
• @ASCII short answer: each photon is a wave. All waves have a frequency
– Jim
Commented Feb 24, 2017 at 15:20
• That's the problem with photon , you can't visualize it in an easy way, I think of it as a small localized chunk of wave, so when you say frequency of photon that just means the frequency of that wave chunk, which is same as the frequency of light. Commented Feb 24, 2017 at 15:48
• Commented Feb 25, 2017 at 10:28

ASCII in his comment to Wojciech Morawiec answer asked

how does a single photon have a frequency

To understand this one has to recognize that the emission of photons takes place from electrons as well as from protons. Both subatomic particles have the intrinsic properties of an own magnetic field and an own electric field. Unfortunately the inner structure of this fields is unknown but it can be stated that both fields around this particles coexist.

Both particles could receive photons. By this they get excited in relation to the surrounding particles and shortly "try" to fall back in the common state, emitting by this photons. To get a macroscopic and measurable effect of the emission of photons the invention of the radio waves was helpful. In a antenna rod electrons get accelerated forth- and backwards periodically and during this excitations they emit more or less synchronously photons. It was found out that the common wave of this photons has a electric field component parallel to the rod and a common magnetic field perpendicular to the rod. In the near field it looks like this:

E is the electric field, B is the magnetic. Following with our finger the k-axis watch the amplitudes of the two field components. Imaginary moving your finger with the speed of light you would simulate a moving photon. It's like a bubble expanding to the left and right and than up and down and so on. Photons of different frequencies have different lengths between every full oscillation. The different "bubbles" are of different diameter dependent from their frequency and by this of different energy.

Does all the photons have the same energy?

Definitely not.