The basis of the quantum mechanical model of an atom is:

The ratio of de-Broglie wavelengths of two particles having mass ratio $1:3$ and kinetic energy ratio $2:1$ is

An electron moves in an electric field with a kinetic energy of $2.5 \, eV$. The de Broglie wavelength associated with it is .....

The kinetic energy (in $J$) of a particle of mass $4.5 \times 10^{-31} \ kg$ having a wavelength of $1000 \ nm$ is : $(h = 6.62 \times 10^{-34} \ J \ s)$

The energy of separation of an electron in a $H$ atom in an excited state is $3.4 \ eV$. The de-Broglie wavelength (in $\mathring{A}$) associated with the above electron is,if the radius of the first orbit of the $H$ atom is $0.53 \ \mathring{A}$.

The wavelength of a photon is $5200 \ \mathring{A}$. At what velocity will an electron have the same wavelength as this photon (in $m/s$)?