Question

Question: A coherent light with a wavelength 1 = 625 nm illuminates a double slit setup with a slit spacing of d = 0.031 mm. The intensity of light is measured along a distant screen at different angles. When one slit is covered the intensity on the screen is lo = 12.97 W/m². In this problem ignore any effects due to diffraction of light around the slits. K O ........ Screen Figure 1. Coherent light of wavelength à is incident on two slits separated by a distance d with an observation screen behind. The point of interest on the observation screen is an angle from the horizontal at the centre of the two slits. The sketch is not to scale: the screen distance is >> d. Part 1) What is the maximum intensity observed at any point on the screen? Imax = W/m² Part 2) What is the average intensity observed on the screen? lavg = W/m2

Answer 1

d= 0.031 mm = 301210-5 m. d=625 mm= 625x16m. Intensity through I sit 2 = 12.97 Wome Imax = 45 lat constructive interferences = 4x 1.-97. Imax = 51.88 W/m2) o ® we know intensity distribution ma double slit set up is I = Imas cos? (0) Averaging cos? ( 6 ) over dit becomes 0.5 Imax Lang=0.5 851.88 = 25.94 Were ļ ♡ we know angle Pornth bright be in screen On=nd 0.12 gadi Therefore Op=6X625x10m - 3.1810-S