Atoms and Nuclei

A radioactive nucleus emits \(4 \alpha\)-particles and \(7 \beta\)-particles in succession. The ratio of number of neutrons of that of protons, is [\(A=\) mass number, \(Z=\) atomic number]

The ratio of energies of photons produced due to transition of electron of hydrogen atom from its (i) second to first energy level and (ii) highest energy level to second level is respectively

In hydrogen emission spectrum, for any series, the principal quantum number is $n$. Corresponding maximum wavelength $\lambda$ is ( $R=$ Rydberg's constant)

If the speed of an electron of hydrogen atom in the ground state is $2.2 \times 10^6 \mathrm{~m} / \mathrm{s}$, then its speed in the third excited state will be

The wavelength of the first line in Balmer series in the hydrogen spectrum is ' $\lambda$ '. What is the wavelength of the second line in the same series?

Bohr model is applied to a particle of mass ' $m$ ' and charge ' $q$ ' is moving in a plane under the influence of a transverse magnetic field ' $B$ '. The energy of the charged particle in the $n$th level will be ( $h=$ Planck's constant)

The angle made by orbital angular momentum of electron with the direction of the orbital magnetic moment is

In Balmer series, wavelength of first line is ' $\lambda_1$ ' and in Brackett series wavelength of first line is ' $\lambda_2$ ' then $\frac{\lambda_1}{\lambda_2}$ is

When the electron in hydrogen atom jumps from fourth Bohr orbit to second Bohr orbit, one gets the