A nucleus ${ }_n^m X$ emits one $\alpha$-particle and two $\beta^{-}$particles. The resulting nucleus is

A nucleus ${ }_n^m X$ emits one $\alpha$-particle and two $\beta^{-}$particles. The resulting nucleus is
  1. ${ }_n^{m-6} Z$
  2. ${ }_n^{m-4} X$
  3. ${ }_{n-2}^{m-4} Y$
  4. ${ }_{n-4}^{m-6} Z$

Solution

${ }_n^m X \stackrel{\alpha}{\rightarrow}{ }_{n-2} X^{m-4} \stackrel{2 \beta}{\rightarrow}{ }_n X^{m-4}$

Asked in: NEET 2011 (Screening)

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