Physics Logo
HOME TOPICS DEFINITIONS TABLES LAWS INVENTIONS EXPERIMENTS QUIZ VIDEOS
A B C D E F G H I J K L M
N O P Q R S T U V W X Y Z
Gamma Decay ( √ Decay )
The phenomenon of emission of gamma ray photon from a radioactive substance is called gamma decay.
Gamma rays are photons of very high energy. A number of experiments suggest that protons and neutrons occupy discrete energy states, similar to the energy states occupied by electrons in atoms.
In other words, a nucleus like an atom can exist in excited states as well as in its ground state. Following α or β decay, the daughter nucleus may be left in one of these excited states.
When the nucleus makes a transition from a higher energy state (E2) to a lower energy state (E1), then it will emit a √ ray photon of frequency,
E2 - E1  =  hf
This is analogous to the emission of a photon by an atom as its orbital electron jumps from higher energy state to a lower energy state.
It may be noted that the energy levels of a nucleus are of the order of keV or MeV as compared to a few eV for electrons in an atom. Hence the emitted photons have energies that can range from a few keV to several MeV.
Since a √-ray carries no charge, there is no change in the element as a result of emission of a √-ray.
o DISCLAIMER         o CONTACT US