In the gamma decay of a nucleus

In the gamma decay of a nucleus

the mass number of the nucleus changes whereas its atomic number does not change
the mass number of the nucleus does not change whereas its atomic number changes
both the mass number and the atomic number of the nucleus change
neither the mass number nor the atomic number of the nucleus changes
This question was previously asked in
UPSC CDS-2 – 2016
In the gamma decay of a nucleus, neither the mass number nor the atomic number of the nucleus changes.
– Gamma decay is a type of radioactive decay where an atomic nucleus in an excited state emits a gamma ray photon.
– A gamma ray is high-energy electromagnetic radiation and has no mass or charge.
– The emission of a gamma ray allows the nucleus to transition from a higher energy level to a lower energy level.
– Since no particles (protons or neutrons) are emitted or transformed, the number of protons (atomic number, Z) and the total number of nucleons (mass number, A) in the nucleus remains unchanged.
– Alpha decay decreases A by 4 and Z by 2. Beta decay increases Z by 1 (β⁻ decay) or decreases Z by 1 (β⁺ decay) while A remains unchanged.
Gamma decay often occurs after alpha or beta decay, when the daughter nucleus is left in an excited state. The excited nucleus de-excites by emitting one or more gamma rays.
Exit mobile version