If the velocities of hydrogen $(H_2)$ and helium $(He)$ molecules are equal,then the ratio of the wavelengths of helium to hydrogen is .......

The de-Broglie wavelength of a particle with mass $1 \, g$ and velocity $100 \, m/sec$ is

The velocity of an electron is $1\%$ of the velocity of light. Calculate the de-Broglie wavelength of the electron.

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

Which of the following relations is correct, if the wavelength $(\lambda)$ is equal to the distance travelled by the electron in one second? $h$ is the Planck's constant and $m$ is the mass of electron.

If $v_0$ is the threshold frequency of a metal $X$,the correct relation between de Broglie wavelength $(\lambda)$ associated with the photoelectron and the frequency $(v)$ of the incident radiation is: