JEE Main · 2022 · 28 Jul 2022 · Shift 1 · Wave Optics

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In a Young's double slit experiment, a laser light of 560 nm produces an interference pattern with consecutive bright fringes' separation of 7.2 mm . Now another light is used to produce an interference pattern with consecutive bright fringes' separation of 8.1 mm . The wavelength of second light is ____ nm .

Answer: 630

Solution

Fringe width

β \propto λ

. Thus

\frac{β _{2}}{β _{1}} = \frac{λ _{2}}{λ _{1}}

. Given

\frac{8.1}{7.2} = \frac{9}{8}

, we have

λ_{2} = \frac{9}{8} \times 560 = 630

nm.

JEE Main · 2022 · 28 Jul 2022 · Shift 1 · Integer answer

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