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| Gamma Decay ( √ Decay ) |
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The phenomenon of emission of gamma ray photon from a radioactive substance is called gamma decay. |
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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. |
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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.
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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, |
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E2 - E1 = hf
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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. |
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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. |
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Since a √-ray carries no charge, there is no change in the element as a result of emission of a √-ray.
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