The ground state energy of hydrogen atom is $$-13.6 \mathrm{~eV}$$. If the electron jumps from the $$3^{\text {rd }}$$ excited state to the ground state then the energy of the radiation emitted will be:

In the head-on collision of two alpha particles $$\alpha_1$$ and $$\alpha_2$$ with the gold nucleus, the closest approaches are 31.4 fermi and 94.2 fermi respectively. Then the ratio of the energy possessed by the alpha particles $$\alpha_2 / \alpha_1$$ is:

Which of the following statement is true when a gamma decay occurs from the nucleus of an atom?

During $$\alpha$$-decay, atomic mass of parent nuclei is