$A$ body of mass $x$ $kg$ is moving with a velocity of $100$ $ms^{-1}$. Its de-Broglie wavelength is $6.62 \times 10^{-35}$ $m$. Hence,$x$ is ($h = 6.62 \times 10^{-34}$ $Js$). (in $kg$)

If the wavelength of a photon is $2.2 \times 10^{-11} \ m$ and $h = 6.6 \times 10^{-34} \ J \ s$,then the momentum of the photon is:

If the kinetic energy of an electron is $18.2 \times 10^{-25} \ J$,its de Broglie wavelength in $nm$ is: (mass of electron $= 9.1 \times 10^{-31} \ kg$; $h = 6.626 \times 10^{-34} \ J \ s$)

The de-Broglie wavelength associated with a material particle is

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 $0.53 \ \mathring{A}$.

If the velocities of hydrogen $(H_2)$ and helium $(He)$ molecules are equal,then the ratio of the wavelengths of helium to hydrogen is .......