According to classical theory,the proposed circular path of an electron in Rutherford atomic model will be:

Among the following,which transition in the hydrogen spectrum would have the same wavelength as the Balmer transition,$n=4$ to $n=2$ in the $He^{+}$ spectrum?

Calculate the longest wavelength in the hydrogen emission spectrum of the Lyman series $\left(R_H = 109677 \ cm^{-1}\right)$.

If the electron jumps from $7.00 \ eV$ energy level to $5.0 \ eV$ energy level,it :

The energy of an electron in the first Bohr orbit of the hydrogen atom is $-13.6 \ eV$. Calculate the energy of an electron in the first Bohr orbit of $He^{+}$ in $eV$.

The surface of sodium metal is irradiated with radiation of wavelength $x$ nm. The kinetic energy of ejected electrons is $2.8 \times 10^{-20}$ $J$. The work function of sodium is $2.3$ eV. The value of $x$ is . . . . . . $\times 10^2$ nm.