Question

Monochromatic light is incident on a grating that is 75 mm wide and ruled with 50,000 lines. The second-order maximum is seen at 32.5°. What is the wavelength of the incident light? 202 nm 605 nm 806 nm 403 nm 452 nm

Answer 1

Answer:

= 403 nm

Explanation:

We have the condition for the maximum for a diffraction grating

                                     d sinθ =mλ

Then the grating constant d = w/N

                                    = (75 mm)/(50,000)

                                      = 0.0015 mm

Then wavelength of light is λ = (dsinθ)/m

                                        = (0.0015 mm)(sin 32.5)/2

                                     =403*10-6 mm

                                        = 403 nm