Question: Q. 4. (a) Draw a plot showing the variation of potential energy of a pair of nucleons as a function of their separation. Mark the regions where the nuclear force is
(i) attractive and (ii) repulsive.
In the nuclear reaction
$$ { }{0} n^{1}+{ }{92}^{235} \mathrm{U} \rightarrow{ }{54}^{a} \mathrm{Xe}+{ }{b}^{94} \mathrm{Sr}+2{ }_{0} n^{1} $$
determine the values of $a$ and $b$.
[CBSE Comptt. 2018]
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Solution:
Ans. (a) Drawing the plot Marking the relevant regions 1 (b) Finding values of $a$ and $b$
(a)
For $r>r_{0}$, the force is attractive
For $r<r_{0}$, the force is repulsive
(b) We have,
$$ \begin{array}{rlrl} & & 1+235 & =a+94+2 \times 1 \ & \therefore & a & =236-96=140 \ & \text { Also } & 0+92 & =54+b+2 \times 0 \ \therefore & b & =92-54=38 \end{array} $$
[CBSE Marking Scheme 2018]
