A nucleus with mass number 242 and binding energy per nucleon as $$7.6~ \mathrm{MeV}$$ breaks into two fragment each with mass number 121. If each fragment nucleus has binding energy per nucleon as $$8.1 ~\mathrm{MeV}$$, the total gain in binding energy is _________ $$\mathrm{MeV}$$.

The momentum of a body is increased by $$50 \%$$. The percentage increase in the kinetic energy of the body is ___________ $$\%$$.

An electric dipole of dipole moment is $$6.0 \times 10^{-6} ~\mathrm{C m}$$ placed in a uniform electric field of $$1.5 \times 10^{3} ~\mathrm{NC}^{-1}$$ in such a way that dipole moment is along electric field. The work done in rotating dipole by $$180^{\circ}$$ in this field will be ___________ $$\mathrm{m J}$$.

Two vertical parallel mirrors A and B are separated by $$10 \mathrm{~cm}$$. A point object $$\mathrm{O}$$ is placed at a distance of $$2 \mathrm{~cm}$$ from mirror $$\mathrm{A}$$. The distance of the second nearest image behind mirror A from the mirror $$\mathrm{A}$$ is _________ $$\mathrm{cm}$$.