If the series limit of wavelength of the Lyman series for the hydrogen atom is $912 \ \mathring{A}$,then the series limit of wavelength for the Balmer series of radiation which may be emitted is :

$A$ source of monochromatic radiation of wavelength $400 \, nm$ provides $1000 \, J$ of energy in $10 \, seconds$. When this radiation falls on the surface of sodium,$x \times 10^{20}$ electrons are ejected per second. Assume that wavelength $400 \, nm$ is sufficient for ejection of electrons from the surface of sodium metal. The value of $x$ is $......$. (Nearest integer) $(h = 6.626 \times 10^{-34} \, Js)$

Which of the following transitions has the minimum wavelength?

Which transition in a $H$ atom emits the maximum energy?

The energies of an electron in the first orbit of $He^{+}$ and in the third orbit of $Li^{2+}$ in $J$ are respectively:

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