The de-Broglie equation is:

Number of waves formed by a Bohr electron in one complete revolution in its third orbit is

The two particles $A$ and $B$ have de Broglie wavelengths $1 \ nm$ and $5 \ nm$ respectively. If the mass of $A$ is four times the mass of $B$,the ratio of kinetic energies of $A$ and $B$ would be

The mass of a particle is $1 \, mg$ and its velocity is $4.5 \times 10^5 \, cm/s$. What will be the wavelength of this particle? $(h = 6.652 \times 10^{-27} \, erg \cdot s)$.

If the radius of the first Bohr orbit of a hydrogen atom is $a_0$, what will be the de Broglie wavelength of an electron in its third excited state (in $\pi a_0$)?

For the quantization of the Bohr orbit,its circumference will be equal to .......