Simulations

Instructions
A simulation will only respond to keyboard control when it is "in focus". If not you can click on the simulation area once to bring it to focus.

Photoelectric Effect

When light shines on a piece of metal, sometimes electrons are released. The electrons, represented by the red dots, are trapped by the potential well of the metal. The energy of the incoming photons is proportional to the frequency and hence inversely proportional to the wavelength. If the photons are energetic enough, they could release the electrons from the potential well. The plate on the top represent a negative electrode, which repels the electrons downward with a constant electric field. If the stopping potential is high enough, no electrons can arrive at the electrode to cause a current, but if the stopping potential is low enough, then a current will flow. The stopping potential is found by adjusting the electrode until the current vanishes.

Quantum Double Slit Interference

When light shines on a piece of metal, sometimes electrons are released. The electrons, represented by the red dots, are trapped by the potential well of the metal. The energy of the incoming photons are proportional to the frequency and hence inversely proportional to the wavelength. If the photons are energetic enough, they could release the electrons from the potential well. The plate on the top represent a negative electrode, which repels the electrons downward with a constant electric field. If the stopping potential is high enough, no electrons can arrive at the electron to cause a current, but if the stopping potential is low enough, then a current will start to flow. The stopping potential is found by adjusting the electrode so that the current just drop to zero.