In the set up shown in the Fig the two slits, S1 and S2 are not equidistant from the slit S. The central fringe at O is then:
Correct answer: C. Either dark or bright depending on the position of S
- A. Always bright
- B. Always dark
- C. Either dark or bright depending on the position of S
- D. Neither dark nor bright.
Explanation
When the slits are not equidistant, the central fringe at O can vary in brightness. This is because the path length difference between the two slits and the central point will impact the interference pattern. If the path length difference is a multiple of the wavelength, the central fringe will be bright; if it is half a wavelength or an odd multiple of half a wavelength, the central fringe will be dark. The other options are incorrect as they do not consider the impact of the slit positions on the interference pattern.
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Light is studied through reflection, refraction, dispersion, interference, diffraction and polarization, linking ray behavior with its wave nature. Questions may involve mirrors, lenses, optical instruments, refractive index and image formation, while geometrical optics deals with rays and wave optics explains effects such as interference and diffraction.
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