The wavelength associated with the motion of an electron:

The de-Broglie wavelength $(\lambda)$ for electron $(e)$, proton $(p)$ and $He^{2+}$ ion $(\alpha)$ are in the following order. (Speed of $e$, $p$ and $\alpha$ are the same)

The wavelength of an electron and a neutron will become equal when the velocity of the electron is $x$ times the velocity of the neutron. The value of $x$ is (Nearest Integer). (Mass of electron is $9.1 \times 10^{-31} \ kg$ and mass of neutron is $1.6 \times 10^{-27} \ kg$)

What is the de-Broglie wavelength associated with the hydrogen electron in its third orbit?

The atomic masses of helium and neon are $4.0$ and $20.0 \ amu$ respectively. The value of the de Broglie wavelength of helium gas at $-73^{\circ} C$ is $M$ times the de Broglie wavelength of neon at $727^{\circ} C$. The value of $M$ is

The de Broglie wavelength of a particle is $1000 \ nm$. What is its momentum? $(h = 6.6 \times 10^{-34} \ J \ s)$