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 wavelength of a tennis ball of $60 \ g$ moving with a velocity of $10 \ m/s$ is approximately

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 $1.6 \times 10^{-27} \ kg$)

Given the ratio of kinetic energy of an electron in two orbitals is $16:9$. Calculate the ratio of the wavelength of the electron waves.

If the kinetic energy of an electron of mass $9.0 \times 10^{-31} \ kg$ is $8.0 \times 10^{-25} \ J$,the wavelength of this electron in $nm$ is

The de-Broglie wavelength of a tennis ball of mass $60 \ g$ moving with a velocity of $10 \ ms^{-1}$ is approximately . . . . . . (Planck's constant $h = 6.63 \times 10^{-34} \ J \cdot s$).