valosähköisellä

Valosähköisellä refers to the photoelectric effect, a phenomenon where electrons are emitted from a material when light shines on it. This effect is fundamental to understanding the interaction between light and matter. The energy of the incident photons must be greater than the work function of the material for electrons to be ejected. If the photon energy is insufficient, no electrons will be emitted, regardless of the light's intensity. Conversely, if the photon energy exceeds the work function, the excess energy is converted into the kinetic energy of the emitted electrons. This relationship between photon energy and electron emission was a key piece of evidence supporting the quantum nature of light. Albert Einstein's explanation of the photoelectric effect, for which he received the Nobel Prize, proposed that light is composed of discrete packets of energy called photons. The photoelectric effect has numerous practical applications, including in solar cells, light meters, and photomultiplier tubes. It is a cornerstone of quantum physics and has profoundly influenced our understanding of the universe.