Optics 6 Question 41

43. In Young’s double-slit experiment, the two slits act as coherent sources of equal amplitude $A$ and of 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 the intensity of light at the mid-point of the screen in the first case to that in the second case is ……

$(1986,2 M)$

True / False

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Solution:

  1. In case of YDSE, at mid-point intensity will be $I _{\max }=4 I _0$ In the second case when sources are incoherent, the intensity will be $I=I _0+I _0=2 I _0$

Therefore, the desired ratio is

$$ \frac{4 I _0}{2 I _0}=2 $$

Here, $I _0$ is the intensity due to one slit.



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