The figure that is not a direct manifestation of the quantum nature of atoms is:

The ground state energy of $H$ is equal to

If change in energy $(\Delta E) = 3 \times 10^{-8} \ J$,$h = 6.64 \times 10^{-34} \ J \cdot s$ and $c = 3 \times 10^8 \ m/s$,then the wavelength of the light is:

The Ritz combination principle states that:

Bohr's atomic model is applicable to which of the following?

$A$ metal surface is exposed to $500 \ nm$ radiation. The threshold frequency of the metal for photoelectric current is $4.3 \times 10^{14} \ Hz$. The velocity of the ejected electron is $....... \times 10^{5} \ ms^{-1}$ (Nearest integer).
[Use : $h=6.63 \times 10^{-34} \ Js, m_{e}=9.0 \times 10^{-31} \ kg$]