MCQ
The slits in a Young's double slit experiment have equal width and the source is placed symmetrically with respect to the slits. The intensity at the central fringe is $I_0$. If one of the slits is closed, the intensity at this point will be:
  • A
    $\text{I}_0$
  • $\frac{\text{I}_0}{4}$
  • C
    $\frac{\text{I}_0}{2}$
  • D
    $4\text{I}_0$

Answer

Correct option: B.
$\frac{\text{I}_0}{4}$
Total intensity coming from the source is $I_0$ which is present at the central maxima. In case of two slits, the intensity is getting distributed between the two slits and for a single slit, the amplitude of light coming from the slit is reduced to half which leads to $\frac{1}{4}\text{th}$ of intensity.

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