Which of the following has the lowest de Broglie wavelength $\lambda$?

The wavelength of the electron emitted by a metal sheet of work function $4 \ eV$ when photons from $EMR$ of wavelength $124 \ nm$ strike the metal plate is ........... $nm$.

The basis of the quantum mechanical model of an atom is:

The mass of a particle is $1 \, mg$ and its velocity is $4.5 \times 10^5 \, cm/s$. What will be the wavelength of this particle? $(h = 6.652 \times 10^{-27} \, erg \cdot s)$.

Which of the following expressions represents the de-Broglie relationship?

$A$ proton accelerated through a potential $V$ has de-Broglie wavelength $\lambda$. Then the de-Broglie wavelength of an $\alpha$-particle,when accelerated through the same potential $V$ is :