In Bohr model of hydrogen atom, the force on the electron depends on the principal quantum number as
$F \propto 1/{n^3}$
$F \propto 1/{n^4}$
$F \propto 1/{n^5}$
Does not depend on $n$
Ratio of longest wavelengths corresponding to Lyman and Balmer series in hydrogen spectrum is
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
Explain Rutherford's argument for scattered $\alpha $ -particles.
The number of completely filled shells for the element ${ }_{16} S ^{32}$ is
Answer the following questions, which help you understand the difference between Thomson's model and Rutherford's model better.
$(a)$ Is the average angle of deflection of $\alpha$ -particles by a thin gold foil predicted by Thomson's model much less, about the same, or much greater than that predicted by Rutherford's model?
$(b)$ Is the probability of backward scattering (i.e., scattering of $\alpha$ -particles at angles greater than $90^{\circ}$ ) predicted by Thomson's model much less, about the same, or much greater than that predicted by Rutherford's model?
$(c)$ Keeping other factors fixed, it is found experimentally that for small thickness $t,$ the number of $\alpha$ -particles scattered at moderate angles is proportional to $t$. What clue does this linear dependence on $t$ provide?
$(d)$ In which model is it completely wrong to ignore multiple scattering for the calculation of average angle of scattering of $\alpha$ -particles by a thin foil?