Q138 / 180 · KCET 2009 · Physics
$\beta$-decay means emission of electron from
- Ainnermost electron orbit
- Ba stable nucleus
- Coutermost electron orbit
- Correct answerDradioactive nucleus
Solution
$\beta$-emission takes place from a radioactive nucleus as
${ }_{15}^{32} \mathrm{P} \stackrel{-\beta}{\longrightarrow}{ }_{16}^{32} \mathrm{~S}+{ }_{-1} \mathrm{e}^{0}+\overline{\mathrm{v}}$
where $\bar{v}$ is the anti-neutrino.
In $\beta^{+}$decay a positron is emitted as
${ }_{11}^{22} \mathrm{Na} \longrightarrow{ }_{10}^{22} \mathrm{Ne}+{ }_{+1} \mathrm{e}^{0}+\mathrm{v}$
where $v$ is the neutrino.
Hence, the correct answer is option: 'D'.