In Young's double-slit experiment, the light emitted from the source has l = 6.5 x 10^-7 m and the distance between the two slits is 1 mm. The distance between the screen and the slit is 1 meter. Distance between the third dark and fifth bright fringe will be:
Correct answer: B. 1.63 mm
- A. 3.2 mm
- B. 1.63 mm
- C. 0.585 mm
- D. 2.31 mm
Explanation
Fringe position y = m λ D / d (bright) and dark at (m+½)λD/d. Compute positions for third dark (m=2 dark → y = (2.5)λD/d) and fifth bright (m=5 → y = 5λD/d); difference = (5 − 2.5)λD/d = 2.5λD/d ≈ 1.63 mm.
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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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