The binding energy per nucleon of $^{209}_{83}Bi$ is . . . . . . MeV. [Take $m(^{209}_{83}Bi) = 208.980388 \text{ u}$,$m_p = 1.007825 \text{ u}$,$m_n = 1.008665 \text{ u}$,$1 \text{ u} = 931 \text{ MeV}/c^2$]

The binding energy for the following nuclear reactions are expressed in $MeV$.
${ }_2 He ^3+{ }_0 n ^1 \rightarrow{ }_2 He ^4+20 \ MeV$
${ }_2 He ^4+{ }_0 n ^1 \rightarrow{ }_2 He ^5-0.9 \ MeV$
If $X_3, X_4, X_5$ denote the stability of ${ }_2 He ^3, { }_2 He ^4$ and ${ }_2 He ^5$,respectively,then the correct order is:

If the speed of light were $2/3$ of its present value,the energy released in a given atomic explosion will be decreased by a fraction:

${ }_{92}^{238} A \rightarrow{ }_{90}^{234} B +{ }_2^4 D + Q$
In the given nuclear reaction,the approximate amount of energy released will be $.....\,MeV$.
[Given: mass of ${ }_{92}^{238} A = 238.05079 \, u$,mass of ${ }_{90}^{234} B = 234.04363 \, u$,mass of ${ }_2^4 D = 4.00260 \, u$,and $1 \, u = 931.5 \, MeV/c^2$]

Which of the following statement$(s)$ is/are true in respect of nuclear binding energy?
$(i)$ The mass energy of a nucleus is larger than the total mass energy of its individual protons and neutrons.
(ii) If a nucleus could be separated into its nucleons,an energy equal to the binding energy would have to be transferred to the particles during the separating process.
(iii) The binding energy is a measure of how well the nucleons in a nucleus are held together.
(iv) The nuclear fission is somehow related to acquiring higher binding energy.

What is the binding energy of the nucleus and binding energy per nucleon? Write their formulas.