A photon is the smallest unit of light or electromagnetic radiation. It is considered both a particle and a wave, and carries energy and momentum.
The photoelectric effect is the phenomenon where electrons are emitted from a metal surface when it is exposed to light. When a photon of sufficient energy collides with an electron in the metal, it can transfer its energy to the electron, causing it to be ejected from the metal.
According to the equation E=hf, where E is energy, h is Planck's constant, and f is frequency, the energy of a photon is directly proportional to its frequency. This means that higher frequency photons have more energy than lower frequency photons.
No, the photoelectric effect cannot be explained by classical physics. Classical physics suggests that increasing the intensity of light should increase the number of electrons emitted, but in reality, the frequency of light is the determining factor for the energy of the emitted electrons.
The photoelectric effect is used in various technologies such as solar panels, photodiodes, and photomultiplier tubes. These devices utilize the conversion of light energy into electrical energy to power devices and detect light. The photoelectric effect also plays a crucial role in photography and image sensors in digital cameras.