An electron having de-Broglie wavelength $\lambda$ is incident on a target in a X-ray tube. Cut-off wavelength of emitted $X$-ray is :
$0$
$\frac{h c}{m c}$
$\frac{2 m^{2} c^{2} \lambda^{2}}{h^{2}}$
$\frac{2 m c \lambda^{2}}{h}$
What radioactive source did the Geiger and Marsden use in the scattering experiment?
Ratio of longest wavelengths corresponding to Lyman and Balmer series in hydrogen spectrum is
The Rutherford $\alpha$-particle experiment shows that most of the $\alpha$-particles pass through almost unscattered while some are scattered through large angles. What information does it give about the structure of the atom
In gold foil experiment number of deflected $\alpha -$ particles at angle $90^o$ is $63$ than number of $\alpha -$ particle deflected at $120^o$ is
From kinetic theory, tell the dimension of an atom.