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Physics · PYQ NEET UG 2019(1)
हिन्दीIn a double slit experiment, when light of wavelength \( 400\text{ nm} \) was used, the angular width of the first minima formed on a screen placed \( 1\text{ m} \) away, was found to be \( 0.2^\circ \). What will be the angular width of the first minima, if the entire experimental apparatus is immersed in water? (\( \mu_{\text{water}} = 4/3 \))
Correct answer · Option 4
\( 0.15^\circ \)
Explanation
Angular width \( \theta = \frac{\lambda}{d} \) depends on wavelength. When immersed in water, wavelength becomes \( \lambda' = \frac{\lambda}{\mu} \). Thus, new angular width \( \theta' = \frac{\theta}{\mu} = \frac{0.2^\circ}{4/3} = 0.15^\circ \).
