For a certain hypothetical one electron atom the wavelength (in $ \mathring A $ ) for the spectral lines for transition from $n = p$ to $n = 1$ are given by $\lambda  = \frac{{1500{p^2}}}{{{p^2} - 1}}$ (where $p > 1$ ), then the ionization potential of this element must be ......$V$ (Take $hc = 12420\ eV- \mathring A $ )

A beam of fast moving alpha particles were directed towards a thin film of gold. The parts $A',\;B'$ and $C'$of the transmitted and reflected beams corresponding to the incident parts $A, B$ and $C$ of the beam, are shown in the adjoining diagram. The number of alpha particles in

Which of the following statements are true regarding Bohr's model of hydrogen atom

$(I)$ Orbiting speed of electron decreases as it shifts to discrete orbits away from the nucleus

$(II)$ Radii of allowed orbits of electron are proportional to the principal quantum number

$(III)$ Frequency with which electrons orbits around the nucleus in discrete orbits is inversely proportional to the principal quantum number

$(IV)$ Binding force with which the electron is bound to the nucleus increases as it shifts to outer orbitsSelect correct answer using the codes given belowCodes :

The radius of the smallest electron orbit in hydrogen-like ion is $(0.51/4 \times 10^{-10})$ metre; then it is

What is impact parameter ? 

Based on which experiment did the Rutherford nuclear model come from?