The diffraction of an electron beam indicates that:

If the radius of the first orbit of the $H$ atom is $a_0$, then the de Broglie wavelength of the electron in the third orbit will be ....... (in $\pi a_0$)

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

What is the de Broglie wavelength of a tennis ball weighing $66 \ g$ moving with a velocity of $10 \ m/s$?

The condition for a stable wave in an orbit of radius $r$ is given by the de Broglie relationship where the circumference of the orbit must be an integral multiple of the wavelength.

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 $= 6.63 \times 10^{-34} \, J \cdot s$