$A$ $20 \, g$ object is moving with a velocity of $100 \, ms^{-1}$. The de Broglie wavelength (in $m$) of the object is [Planck's constant $h = 6.626 \times 10^{-34} \, Js$]

The wavelength of electrons accelerated from rest through a potential difference of $40 \, kV$ is $X \times 10^{-12} \, m$. The value of $X$ is $......$. (Nearest integer)
Given:
Mass of electron $= 9.1 \times 10^{-31} \, kg$
Charge on an electron $= 1.6 \times 10^{-19} \, C$
Planck's constant $= 6.63 \times 10^{-34} \, J \cdot s$

The wavelength associated with the motion of an electron:

The de-Broglie wavelength of a particle of mass $6.63 \ g$ moving with a velocity of $100 \ ms^{-1}$ is

The energy of separation of an electron in a $H$ atom in an excited state is $3.4 \ eV$. The de-Broglie wavelength (in $\mathring{A}$) associated with the above electron is,if the radius of the first orbit of the $H$ atom is $0.53 \ \mathring{A}$.

If the de Broglie wavelength of an electron is $728.14 \ nm$,its kinetic energy in $J$ is: (mass of electron $= 9.1 \times 10^{-31} \ kg$; $h = 6.626 \times 10^{-34} \ J \ s$)