What will be the de Broglie wavelength associated with a charged proton in $\mathring{A}$? ($V =$ potential difference)

What will be the de-Broglie wavelength of an electron moving with a velocity of $1.2 \times 10^5 \ m \ s^{-1}$?

If the kinetic energy of a particle is increased to $4$ times its initial value,how many times will the associated de Broglie wavelength become?

$A$ stream of electrons from a heated filament was passed between two charged plates kept at a potential difference $V$ esu. If $e$ and $m$ are the charge and mass of an electron, respectively, then the value of $h/\lambda$ (where $\lambda$ is the wavelength associated with the electron wave) is given by:

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

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