Describe Geiger-Marsden scattering experiment.
As shown in above figure, they directed a beam of $5.5 \mathrm{MeV} \alpha$-particle emitted from a ${ }_{83}^{214} \mathrm{Bi}$ radioactive source at a thin metal foil made of gold. $\alpha$-particles emitted by a ${ }_{83}^{214} \mathrm{Bi}$ radioactive source were collimated into a narrow beam by their passage through lead bricks. As shown in the figure below, the beam was allowed to fall on a thin foil of gold of thickness $2.1 \times 10^{-7} \mathrm{~m}$.
The scattered $\alpha$-particles on striking the screen produced brief light flashes (scintillations).
These flashes may be viewed through a microscope and the distribution of the number of scattered particles may be studied as a function of angle of scattering.
An $\alpha$- particle of $5\ MeV$ energy strikes with a nucleus of uranium at stationary at an scattering angle of $180^o$. The nearest distance upto which $\alpha$- particle reaches the nucleus will be of the order of
The energy of hydrogen atom in $n^{th}$ orbit is $E_n$, then the energy in $n^{th}$ orbit of singly ionised helium atom will be
The graph which depicts the results of Rutherform gold foil experiment with $\alpha$ -particales is
$\theta:$ Scattering angle
$\mathrm{Y}:$ Number of scattered $\alpha$ -particles detected
(Plots are schematic and not to scale)
Electrons with de-Broglie wavelength $\lambda $ fall on the target an $X-$ ray tube. The cut off wavelength of emitted $X-$ ray is
Explain Rutherford's argument for scattered $\alpha $ -particles.