As an electron makes a transition from an excited state to the ground state of a hydrogen - like atom/ion
kinetic energy decreases, potential energy increases but total energy remains same
kinetic energy and total energy decrease but potential energy increases
its kinetic energy increases but potential energy and total energy decrease
kinetic energy, potential energy and total energy decrease
A proton is fired from very far away towards a nucleus with charge $Q=120 \ e$, where $e$ is the electronic charge. It makes a closest approach of $10 \ fm$ to the nucleus. The de Brogle wavelength (in units of $fm$ ) of the proton at its start is :
(take the proton mass, $m _0=(5 / 3) \times 10^{-27} kg , h / e =4.2 \times 10^{-15} J / s / C ; \frac{1}{4 \pi \varepsilon_0}=9 \times 10^9 m / F ; 1 fm =10^{-15} m$ )
An alpha nucleus of energy $\frac{1}{2}mv^2$ bombards a heavy nuclear target of charge $Ze.$ Then the distance of closest approach for the alpha nucleus will be proportional to
If in Rutherford’s experiment, the number of particles scattered at ${90^o}$ angle are $28$ per min, then number of scattered particles at an angle ${60^o}$ and ${120^o}$ will be
The ratio of the speed of the electrons in the ground state of hydrogen to the speed of light in vacuum is
Energy levels $A, B$ and $C$ of a certain atom correspond to increasing values of energy, i.e. $E_A < E_B < E_C$ . If $\lambda _1, \lambda _2$ and $\lambda _3$ are the wavelengths of radiations corresponding to transitions $C$ to $B, B$ to $A$ and $C$ to $A$ respectively , which of the following relations is correct ?