According to the Rutherford’s atomic model, the electrons inside the atom are

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 :

Hydrogen $(H)$, deuterium $(D)$, singly ionized helium $(He^+)$ and doubly ionized lithium $(Li^{++})$ all have one electron around the nucleus. Consider $n = 2$ to $n = 1$ transition. The wavelengths of emitted radiations are $\lambda_1, \lambda_2 \lambda_3$ and $\lambda_4$ respectively.

In a Geiger-Marsden experiment, what is the distance of closest approach to the nucleus of a $7.7 \;MeV$ $\alpha -$particle before it comes momentarily to rest and reverses its direction?

In Bohr model of hydrogen atom, the force on the electron depends on the principal quantum number as

State the dimension of the nucleus from Rutherford experiment.