Question

Light from an argon laser strikes a dirfraction grating that has 5,166 grooves per centimeter. The central and first-order principal maxima are separated by 0.4B8 m on a wall 1.77 m from the grating. Determine the wavelength of the laser light 463x Your response differs from the comect answer by more than 10%. Double check your calculations. nm centimeter

Answer 1

wavelength in diffraction grating is given by:

m*lambda = d*sin theta

m = 1, since 1st order maxima

lambda = wavelength of laser light = ?

d = distance between slits = 1 cm/5166 slits = 1.936*10^-6 m

sin theta = y/sqrt (y^2 + L^2) = 0.488/sqrt (0.488^2 + 1.77^2)

sin theta = 0.2658

So,

lambda = (d/m)*sin theta

lambda = (1.936*10^-6/1)*0.2658 = 5.146*10^-7 m

lambda = 514.6*10^-9 m = 514.6 nm

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