The de Broglie wavelengths of two fast moving particles $X$ and $Y$ are $1 \ nm$ and $3 \ nm$ respectively. The mass of $X$ is nine times the mass of $Y$. The ratio of kinetic energies of $X$ and $Y$ is:

The de Broglie wavelength of a particle $X$ moving with a certain velocity is $1 \ \mathring{A}$. If the mass of $Y$ is $25\%$ of $X$ and its velocity is $75\%$ of $X$,then the de Broglie wavelength of $Y$ will be ........... $\mathring{A}$.

Wavelength of $H^{+}$ ion with kinetic energy $1.65 \ eV$ is (mass of proton $= 1.6726 \times 10^{-27} \ kg$) (in $nm$)

The mass of an electron is $9.1 \times 10^{-31} \ kg$. If its $K.E.$ is $3.0 \times 10^{-25} \ J$,calculate its wavelength.

Calculate the momentum of a particle which has a wavelength of $1 \ \mathring{A}$.

$A$ ball weighing $25 \, g$ moves with a velocity of $6.6 \times 10^4 \, cm/sec$. The de Broglie wavelength associated with it is .....