From the given data,the amount of energy required to break the nucleus of aluminium ${ }_{13}^{27} {Al}$ is $x \times 10^{-3} {J}$.
Mass of neutron $= 1.00866 \, {u}$
Mass of proton $= 1.00726 \, {u}$
Mass of aluminium nucleus $= 26.98154 \, {u}$
(Assume $1 \, {u}$ corresponds to $1 \, {J}$ of energy for the purpose of this calculation)
(Round off to the nearest integer)

The binding energy of a nucleus is a measure of its

An alpha particle $\left({ }^{4} He\right)$ has a mass of $4.00300 \ amu$. $A$ proton has a mass of $1.00783 \ amu$ and a neutron has a mass of $1.00867 \ amu$. The binding energy of an alpha particle estimated from these data is closest to: (in $MeV$)

Given below are two statements. One is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A) :$ The binding energy per nucleon is found to be practically independent of the atomic number $A$,for nuclei with mass numbers between $30$ and $170$.
Reason $(R) :$ Nuclear force is long range.
In the light of the above statements,choose the correct answer from the options given below $:$

An electron and a positron annihilate each other to produce two $\gamma$-ray photons of equal energy. The minimum energy of each photon is .....

Let ${m_p}$ be the mass of a proton,${m_n}$ the mass of a neutron,${M_1}$ the mass of a $_{10}^{20}Ne$ nucleus,and ${M_2}$ the mass of a $_{20}^{40}Ca$ nucleus. Then: