State the de Broglie principle.

The atomic masses of helium and neon are $4.0$ and $20.0 \ amu$ respectively. The value of the de Broglie wavelength of helium gas at $-73^{\circ} C$ is $M$ times the de Broglie wavelength of neon at $727^{\circ} C$. The value of $M$ is

According to de Broglie,matter should exhibit dual behaviour,that is both particle and wave-like properties. However,a cricket ball of mass $100 \ g$ does not move like a wave when it is thrown by a bowler at a speed of $100 \ km/h$. Calculate the wavelength of the ball and explain why it does not show wave nature.

The mass of a photon with a wavelength equal to $1.54 \times 10^{-8} \ cm$ is

What should be the momentum (in $g \ cm / s$) of a particle if its de Broglie wavelength is $1 \ \mathring{A}$ and the value of $h$ is $6.6252 \times 10^{-27} \ erg \ s$?

Calculate the $\lambda$ associated with an electron moving with the velocity of light.