Fraunhoffer diffraction from a single slit is observed in the focal plane of a lens of focal length 0.6 m. The slit width is 0.2 mm. The second minimum is observed at a distance of 3.3 mm from the central maximum. Then the wavelength of light used is :

Options

A. 5000 A
B. 5500 A
C. 6000 A
D. 6500 A

Answer

B

Explanation

Distance b/w central maximum & second minimum `= (2lamdaD)/a`
3.3 mm `= (2lamdaxx0.6m)/(0.2 mm)`
`lamda=(3.3)/(0.6)xx0.1 xxmm^2 = (3.3)/6 xx10^(-6)`
= 5500 A