Question 215: Waves Optics

Question

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.

Accepted Answer

$$\lambda  = 560 	imes {10^{ - 9}}$$
$${B_1} = 7.2 	imes {10^{ - 3}}$$
$${B_2} = 8.1 	imes {10^{ - 3}}$$
$${{{B_1}} \over {{B_2}}} = {{{\lambda _1}} \over {{\lambda _2}}}$$
$$ \Rightarrow {\lambda _2} = {{560 	imes {{10}^{ - 9}} 	imes 8.1 	imes {{10}^{ - 3}}} \over {7.2 	imes {{10}^{ - 3}}}}$$
$$ = 6.3 	imes {10^{ - 7}}$$ m
$$ = 630$$ nm

Waves Optics

Choose the correct answer: