Maybe this is a stupid question, but I dont understand what force is driving photons in light beams to go up and down, making a sine wave. How often in which it oscillates determines the frequency yeah, but why does it do that in the first place? And why is it that when light is emitted, instead of scattering like individual particles, the photons stay in a line. Like there’s a force that is keeping them in a straight line, and theres a force causing them to oscillate. Maybe they arent forces, but I just don’t get it.
In: Physics
The short version is that a photon is a travelling oscillation of electric and magnetic fields. **The key is that a changing electric field produces a magnetic field and a changing magnetic field produces an electric field**. The fields themselves are at right angles to each other a well as the direction of travel so lets say the electric field is up and down and the magnetic field is left and right while the direction of travel is forward. In this case the cycle looks something like this:
1. When the electric field is increasing upwards, it pushes the magnetic field to the right.
2. When the magnetic field is increasing to the right, it pushes the electric field down.
3. When the electric field is increasing downwards, it pushes the magnetic field left.
4. When the magnetic field is increasing to the left, it pushes the electric field up.
and you’re back at 1 so the cycle repeats.
This cycle of the electric and magnetic fields pushing each other back and forth as they travel forward together is fundamentally what light and all other forms of electromagnetic radiation is. All is needed is some event to cause a change in either the electric or magnetic field to start the cycle and the interaction between the two will take care of the rest.
Latest Answers