Question: Q. 6. (i) Write the basic nuclear process involved in the emission of $\beta^{+}$in a symbolic form, by a radioactive nucleus.
(ii) In the reactions given below :
(a) ${ }{6}^{11} \mathrm{C} \rightarrow{ }{y}^{z} \mathrm{~B}+x$
(b) ${ }{6}^{12} \mathrm{C}+{ }{6}^{12} \mathrm{C} \rightarrow{ }^{20} \mathrm{Ne}+{ }_{b}^{c} \mathrm{He}$
Find the values of $x, y$, and $z$ and $a, b$ and $c$.
A [OD I, II, III 2016]
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Solution:
Ans. (i) Basic nuclear reaction
$$ \begin{align*} & p \rightarrow n+e^{+}+v \ & x=\beta^{+}\left({ }_{1}^{0} e\right), y=5, z=11 \tag{1}\ & a=10, b=2, c=4 . \tag{b} \end{align*} $$
[CBSE Marking Scheme, 2016]
Detailed Answer :
(ii) (a) is $\beta^{+}$decay as neutrino is emitted out. $1 / 2$ Hence there is no change in mass number and -1 change in atomic number.
So, $y=6-1=5$ and $z=11$.
(b) is $\alpha$ decay.
Hence there is four unit change in mass number and two unit change in atomic number.
So,
$$ \begin{aligned} a & =12-2 \ & =10, b=2 \text { and } c=4 . \quad 1 / 2 \end{aligned} $$
