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Physics · PYQ NEET UG 2019(2)
हिन्दीAngular width of the central maxima in the Fraunhoffer diffraction for \( \lambda = 6000 \text{ \AA} \) is \( \theta_0 \). When the same slit is illuminated by another monochromatic light, the angular width decreases by \( 30\% \). The wavelength of this light is
Correct answer · Option C
\( 4200 \text{ \AA} \)
Explanation
Angular width \( \theta \propto \lambda \). Since \( \theta \) decreases by \( 30\% \), new width is \( 70\% \) of original. Thus \( \lambda' = 0.70 \times 6000 = 4200 \text{ \AA} \).
