Calculate the wave number of a photon emitted during the transition from the orbit $n = 2$ to $n = 1$ in a hydrogen atom $(R_{H} = 109677 \ cm^{-1})$. (in $cm^{-1}$)

If the first ionization energy of $H$ atom is $13.6 \ eV,$ then the second ionization energy of $He$ atom is (in $eV$)

Calculate the wavenumber of a photon emitted during the transition from the orbit of $n=3$ to $n=2$ in a hydrogen atom. $(R_{H} = 109677 \ cm^{-1})$ (in $cm^{-1}$)

The value of Planck's constant is $6.63 \times 10^{-34} \, J \cdot s$ and the speed of light is $3.0 \times 10^8 \, m \cdot s^{-1}$. The wavelength of a quantum of light with a frequency of $8 \times 10^{15} \, s^{-1}$ is closest to which of the following values in meters?

In the hydrogen spectrum,if an electron transitions from the $6^{th}$ orbit to the $2^{nd}$ orbit through multiple steps,the number of spectral lines produced is ....

What is the maximum wavelength in the Lyman series of $He^{+}$ ion?