Atoms And Nuclei - Modern Physics - Physics Previous Year Questions

Bose-Einstein statistics is applicable to particles with

In $\beta^{-}$decay, a neutron transforms into a proton within the nucleus according to the equation :

neutron $\rightarrow$ proton $+\beta^{-}+x$

In this equation the particle represented by ' $x$ ' is

The ratio of the kinetic energies of the electrons in the third and fourth excited states of hydrogen atom is

Two radioactive substances $A$ and $B$ have same number of initial nuclei. If the half lives of $A$ and $B$ are 1.5 days and 4.5 days respectively, then the ratio of the number of nuclei remaining in $A$ and $B$ after 9 days is

The average energy of a neutron produced in the fission of ${ }_{92}^{235} \mathrm{U}$ is

If $96.875 \%$ of a radioactive substance decays in 10 days, then the half life of the substance is (in days)

If the difference in the frequencies of the first and second lines of Lyman series of hydrogen atom is $f$, then the difference in frequencies of the first and second lines of Balmer series of hydrogen atom is