JEE Advanced 2013 · Paper 2, Physics question 12

Paragraph for Questions 11 and 12

The mass of a nucleus $^A_Z\mathrm X$ is less than the sum of the masses of $(A-Z)$ number of neutrons and $Z$ number of protons in the nucleus. The energy equivalent to the corresponding mass difference is known as the binding energy of the nucleus. A heavy nucleus of mass $M$ can break into two light nuclei of masses $m_1$ and $m_2$ only if $(m_1+m_2)<M$. Also two light nuclei of masses $m_3$ and $m_4$ can undergo complete fusion and form a heavy nucleus of mass $M'$ only if $(m_3+m_4)>M'$. The masses of some neutral atoms are given in the table below:

Atom	Mass	Atom	Mass
$^1_1\mathrm H$	1.007825 u	$^2_1\mathrm H$	2.014102 u
$^3_1\mathrm H$	3.016050 u	$^4_2\mathrm{He}$	4.002603 u
$^6_3\mathrm{Li}$	6.015123 u	$^7_3\mathrm{Li}$	7.016004 u
$^{70}_{30}\mathrm{Zn}$	69.925325 u	$^{82}_{34}\mathrm{Se}$	81.916709 u
$^{152}_{64}\mathrm{Gd}$	151.919803 u	$^{206}_{82}\mathrm{Pb}$	205.974455 u
$^{209}_{83}\mathrm{Bi}$	208.980388 u	$^{210}_{84}\mathrm{Po}$	209.982876 u

(1 u = 932 MeV/c²)