The radius (in $\mathring{A}$) of the $3^{rd}$ Bohr orbit in $Li^{2+}$ ion is closest to $......$ [Given: Atomic number of $Li = 3$]

Which of the following statements regarding the $H$ atom spectrum is correct?

If the ionization potential of $Li^{2+}$ is $122.4 \ eV$,what is the $5^{th}$ ionization potential of carbon in $eV$?

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

The value of the energy for the first excited state of hydrogen atom will be $............. \ eV$.

What is the wavelength of light emitted when the electron in a hydrogen atom undergoes transition from an energy level with $n=4$ to an energy level with $n=2$ (in $nm$)?