Question

1. Monochromatic blue light of wavelength 440-nm passes through a 3300 lines/cm diffraction grating and the interference pattern is observed on a screen. (a) Determine the interference angle for the 2nd order bright fringe. 15 points) (b) If a screen is 0.75-m away, how far (in cm) is the 2nd order bright fringe from the center? Show all steps. [3 points) (c) Sketch the path taken by this light to reach the center, the 1st and 2nd order bright fringes. In the diagram - Indicate all the parameters, including your answers to part a and b. [6 points) (d) In the above diagram indicate the location for the 2nd order bright fringe if red ligh is used. (no need to show any calculations). [2 points) [2 points) (e) What happens to the light waves as they pass through the narrow slits? A) refraction B) polarization C) diffraction D) dispersion Explain in 1-2 sentences how you made your choice. [2 points)

Answer 1

(a) olm 330000 clines d= (e) light gets diffracted through slits. 33 0000 -9 do 440X10' m d sino med Sin Os 2440 x 10 (330000) sint (0.2904) 16.8819° (6) tan@= tlar (c) ar tau 16.8819° 2 0.75X y 0.22 76 (d) ly If red ligh is used © increases .