Two narrow, parallel slits separated by 0.850 mm are illuminated by 600-nm light, and the viewing screen is 2.80 m away from the slits. (a) what is the phase difference between the two interfering waves on a screen at a point 2.50 mm from the central bright fringe? (b) what is the ratio of the intensity at this point to the intensity at the center of a bright fringe?

a) 7.947 radians

b)

Explanation:

y = Distance from central bright fringe = 2.5 mm

λ = Wavelength = 600 nm

L = Distance between screen and source = 2.8 m

d = Slit distance = 0.85 mm

a) Phase difference

∴ Phase difference between the two interfering waves on a screen at a point 2.50 mm from the central bright fringe is 7.947 radians

b)

∴ Ratio of the intensity at this point to the intensity at the center of a bright fringe

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.