In a Young's double slit experiment, the slits possess equal width, and the source is positioned symmetrically relative to them. The intensity at the central fringe is I₀ . If one of the slits is subsequently blocked, the intensity at this point will become

Step-by-step solution

Let the intensity of light from each slit be I . When both slits are open, the intensity at the central fringe is maximum because the path difference is zero. The resultant intensity is given by I₀ = I + I + 2 I I (0^ ) = 4I . When one of the slits is blocked, there is no interference. The intensity at the central point is solely due to the light from the remaining single slit. Thus, the new intensity is I . From the relation I₀ = 4I , we get I = I₀ 4 .