In the Bohr model of hydrogen,the force on the electron depends on the principal quantum number $n$ as:

For principal quantum number $n = 3$,the possible values of orbital quantum number $l$ are

The time of revolution of an electron around a nucleus of charge $Ze$ in the $n^{th}$ Bohr orbit is directly proportional to

The ratio of the area of the first excited state to the ground state orbit of a hydrogen atom is:

For $He^{+}$, a transition takes place from the orbit of radius $105.8 \ pm$ to the orbit of radius $26.45 \ pm$. The wavelength (in $nm$) of the emitted photon during the transition is. . . . .
[Use: Bohr radius, $a_0=52.9 \ pm$; Rydberg constant, $R_H=2.2 \times 10^{-18} \ J$; Planck's constant, $h=6.6 \times 10^{-34} \ J \ s$; Speed of light, $c=3 \times 10^8 \ m \ s^{-1}$]

In Bohr's model of the hydrogen atom,which of the following pairs of quantities are quantized?