Question

The disintegration energy $Q$ for the changes involving $e^{+}$ decay and $e^{-}$ decay as well as for K-electron capture are given below:
${}_Z^A\text{X}{⟶}_{Z+1}^A\text{Y}+e^{-}+\overline{v};Q=\left[M\right(X]-M(Y\left)\right]\times c^2$
${}_Z^A\text{X}{⟶}_{Z+1}^A\text{Y}+e^{-}+v;Q=\left[M\right(X]-M(Y\left)\right]\times c^2$
${}_Z^A\text{X}+e^{-}{⟶}_{Z+1}^A\text{Y}+v;Q=\left[M\right(X]-M(Y\left)\right]\times c^2$
For either of these decays :

• A. $Q=+ve$ and energy is given out
• B. $Q=+ve$ and energy is absorbed
• C. $Q=-ve$ and energy is given out
• D. $Q=-ve$ and energy is absorbed

Answer 1

The correct option is A $Q=+ve$ and energy is given out

Radioactive changes involving ${\beta }^{-},{\beta }^{+}$ decay or K-electron capture causes mass decay and mass converts into energy according to Einstein as
$E=\Delta m{C}^2=+ve$