In Young's double slit experiment the two slits act as coherent sources of equal amplitude A and wav

Question

In Young's double slit experiment the two slits act as coherent sources of equal amplitude A and wavelength $\lambda$. In another experiment with the same set up the two slits are sources of equal amplitude A and wavelength $\lambda$, but are incoherent. The ratio of intensity of light at the midpoint of the screen in the first case to that in the second case is\

Professor PC Thomas Classes · Answer

Case I:- When the sources are coherent amplitudes get added up.\ $	herefore \mathrm{I}_{1}=(\mathrm{a}+\mathrm{a})^{2}=4 \mathrm{a}^{2}$\ When the sources are incoherent the intensities get added up.\ $	herefore \mathrm{I}_{2}=\mathrm{a}^{2}+\mathrm{a}^{2}=2 \mathrm{a}^{2}$\ $	herefore \frac{\mathrm{I}_{1}}{\mathrm{I}_{2}}=$\