Q 12-10-104JEE MainJEE Main 2022 (28 Jul, Shift 1)Easy
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.
Numerical value type. Enter your answer.
Answer: 630
Fringe width $\beta = \dfrac{\lambda D}{d} \propto \lambda$:
$$\lambda_2 = 560\times\frac{8.1}{7.2} = 630\ \text{nm}$$
Solution by Sreeraj P, M.Sc Physics