The de Broglie wavelength associated with a material particle is ......

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 ratio of de-Broglie wavelength of two particles $A$ and $B$ is $2: 1$. If the velocities of $A$ and $B$ are $0.05 \ ms^{-1}$ and $0.02 \ ms^{-1}$,respectively,then the ratio of their masses $m_A: m_B$ must be

The de Broglie equation describes the relationship between the wavelength associated with the motion of an electron and its:

The de Broglie wavelength of an electron in the third Bohr orbit of $H$-atom is

The wavelength of a moving electron-