To find the ratio of energies of photons produced due to the electron transitions in a hydrogen atom, we need to use the formula for energy in the Bohr model of the hydrogen atom:
E_n = -\frac{13.6 \, \text{eV}}{n^2}
where n is the principal quantum number, and 13.6 eV is the ionization energy of the hydrogen atom.
Let's solve for both scenarios given in the question:
For the transition from the second permitted energy level (n=2) to the first level (n=1):
The energy of the photon is given by the difference in energy levels:
\Delta E_{21} = E_1 - E_2 = \left(-\frac{13.6}{1^2}\right) - \left(-\frac{13.6}{2^2}\right)
\Delta E_{21} = -13.6 + \frac{13.6}{4}
\Delta E_{21} = -13.6 + 3.4 = -10.2 \, \text{eV}
For the transition from the highest permitted energy level (n=\infty) to the first level:
The energy of the photon for a transition from infinity to the first level is:
\Delta E_{\infty 1} = E_1 - E_\infty = \left(-\frac{13.6}{1^2}\right) - 0 = -13.6 \, \text{eV}
The ratio of the energies of the photons produced due to these transitions is:
\frac{\Delta E_{21}}{\Delta E_{\infty 1}} = \frac{-10.2 \, \text{eV}}{-13.6 \, \text{eV}}
\Rightarrow \frac{10.2}{13.6} = \frac{3}{4}
Thus, the required ratio is 3 : 4.