Chapter 20, Problem 20.47QP

Interpretation Introduction

Interpretation:

‘The heavy element such as uranium undergoes fission, but light element like hydrogen and lithium undergo fusion’- should be clarified

Concept introduction:

Nuclear fusion: when two or more than two nuclei is joined together to form a bigger nuclei is called as nuclear fusion.

E.g.-Nuclear fusion occurs in the sun. That’s why sun has unlimited energy and so hot.

In nuclear fusion reaction the 4 hydrogen molecule combines to form 2 helium molecule with liberation of huge amount of energy.

The fusion reaction need more heat energy.so it occurs inside the sun .

A representative reaction is

$\begin{array}{l}{}_{\text{1}}^{\text{2}}{\text{H+}}_{\text{1}}^{\text{2}}\text{H}\stackrel{}{\to }{\text{He}}_{\text{2}}^{\text{3}}\\ {\text{He}}_{\text{2}}^{\text{3}}{\text{+He}}_{\text{2}}^{\text{3}}\stackrel{}{\to }{\text{He}}_{\text{2}}^{\text{4}}{\text{+2}}_{\text{1}}^{\text{1}}\text{H}\\ {\text{H}}_{\text{1}}^{\text{1}}{\text{+H}}_{\text{1}}^{\text{1}}\stackrel{}{\to }{\text{H}}_{\text{1}}^{\text{2}}{\text{+β}}_{\text{-1}}^{\text{0}}\end{array}$

Nuclear fission:

It is the process in which a heavy nucleolus (whose mass number greater than the 200) splits into form smaller nuclei of intermediate mass and one more neutrons.

A large atomic nuclei gets decomposed due to bombardment of some subatomic particle forming one or more than one.

A representative reaction is

${\text{U}}_{\text{92}}^{\text{235}}{\text{+n}}_{\text{0}}^{\text{1}}\stackrel{}{\to }{\text{Sr}}_{\text{38}}^{\text{90}}{\text{+Xe}}_{\text{54}}^{\text{143}}{\text{3n}}_{\text{0}}^{\text{1}}$

To explain: The reason for the given statement