Consider the nuclear fission reaction ${ }_0^1 n+{ }_{92}^{235} \mathrm{U} \longrightarrow{ }_{56}^{144} \mathrm{Ba}+{ }_{36}^{89} \mathrm{Kr}+3{ }_0^1 n$. Assuming all the kinetic energy is carried away by the fast neutrons only and total binding energies of ${ }_{92}^{235} \mathrm{U},{ }_{56}^{144} \mathrm{Ba}$ and ${ }_{36}^{89} \mathrm{Kr}$ to be $1800 \mathrm{MeV}, 1200$ MeV and 780 MeV respectively, the average kinetic energy carried by each fast neutron is (in MeV)
The natural logarithm of the activity $R$ of a radioactive sample varies with time $t$ as shown. At $t=0$, there are $N_0$ undecayed nuclei. Then, $N_0$ is equal to [Take $e^2=7.5$ ]
In the Rutherford's alpha scattering experiment, as the impact parameter increases, the scattering angle of the alpha particle
Three energy levels of hydrogen atom and the corresponding wavelength of the emitted radiation due to different electron transition are as shown. Then,
