The de-Broglie's wavelength of an electron in the $4^{th}$ orbit is . . . . . . . . $\pi a_0$. ($a_0 =$ Bohr's radius)

What will be the wavelength of a ball of mass $0.1 \,kg$ moving with a velocity of $10 \,m \,s^{-1}?$

Calculate the wavelength (in nanometer) associated with a proton moving at $1.0 \times 10^3 \ m \ s^{-1}$. (Mass of proton $= 1.67 \times 10^{-27} \ kg$ and $h = 6.63 \times 10^{-34} \ J \ s$)

If the de Broglie wavelength of an electron is $728.14 \ nm$,its kinetic energy in $J$ is: (mass of electron $= 9.1 \times 10^{-31} \ kg$; $h = 6.626 \times 10^{-34} \ J \ s$)

Which is the correct relationship between wavelength and momentum of particles?

The relationship between the momentum $(P)$ and the wavelength $(\lambda)$ of a particle is given by: