Question

Monochromatic light of wavelength 550 nm passes through a diffraction grating that has 55000 lines/m. A bright line appears on the screen at an angle of 12.23o from the central bright fringe. What is the order of this bright line?

Answer 1

Diffraction can be defined as the deviation from rectilinear propagation and the diffraction grating is used for measuring the wavelength of light using spectrometer , the problem given here dsin theta = n lambda and for this problem
Theta is 12.3 deg. , lambda wave length 550 nano meter and grating width can be found from 55000 line /m as d=1/n then we will get the result as n = (sin 12.23/55000)/550^-9)