Department of Pre-University Education, Karnataka course PUC Karnataka Science Class 12
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# In Which of the Following Decays the Element Does Not Change? - Physics

#### Question

In which of the following decays the element does not change?

• α-decay

•  β+-decay

• β-decay

• γ-decay

#### Solution

γ-decay

​In alpha particle decay, the unstable nucleus emits an alpha particle reducing its proton number Z by 4 and neutron number N by 2 such that the element gets changed.

""_Z^AX → ""_(Z-2)^(A-4)Y + ""_2^4He

During  β-decay​,  a neutron is converted to a proton​, an electron and an antineutrino, i.e. an active nucleus gets converted to one of its isobars and hence the element gets changed.

""_Z^AX → "_(Z+1)^AY + e + barnu

During  β+-decay​,  a proton in the nucleus is converted to a neutron​, a positron and a neutrino in order to maintain the stability of the nucleus, i.e. an active nucleus gets converted to one of its isobars and hence the element gets changed .

""_Z^AX → "_(Z-1)^AY + β^+ + nu

When a nucleus is in higher excited state or has excess of energy, it comes to the ground state in order to become stable and release energy in the form of electromagnetic radiation called gamma ray. Hence, the element in gamma decay doesn't change.

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#### APPEARS IN

HC Verma Solution for Concepts of Physics - Vol. 2 (2018 to Current)
Chapter 24: The Nucleus
MCQ | Q: 5 | Page no. 441
Solution In Which of the Following Decays the Element Does Not Change? Concept: Radioactivity - Gamma Decay.
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