Atomic Physics Theory MCQ Question with Answer

Question No : 15
The velocity of an electron in its fifth orbit, if the velocity of an electron in the second orbit of sodium atom (atomic number = 11) is $\mathcal{v}$, will be :

Question No : 16
The KE of the electron in an orbit of radius r in hydrogen atom is : (e = electronic charge)

Question No : 17
In the lowest orbit, the binding energy of an electron in hydrogen atom is 13.6 eV. The energy required to take out the electron from the lower three orbits in (eV) will be:

Question No : 18
Minimum excitation potential of Bohr's first orbit in hydrogen atom is:

Question No : 19
A proton and an alpha particle having same momentum enter a magnetic field at right angles to it. If $r_1$ and $r_2$ be their radii respectively then value of $\raisebox{1ex}{$r_1$}\!\left/ \!\raisebox{-1ex}{$r_2$}\right.$ is :

Question No : 20
$\alpha$-particles are projected towards the nuclei of the following metals, with the same kinetic energy. Towards, which metal, the distance of closest approach is minimum ?

Question No : 21
An $\alpha$-particle accelerated through V volt is fired towards a nucleus. Its distance of closest approach is r. If a proton accelerated through the same potential is fired towards the same nucleus, the distance of closest approach of proton will be :