Question

1. Violet light with ? = 440nm strikes a double slit and creates an interference pattern on a distant screen.

Part A

At the position of the third-order bright fringe, how much farther is this fringe from the more distant slit than from the closer one?

Express your answer with the appropriate units.

2. A park ranger

Answer 1

1. Path difference for a bright fringe is given as ::

path difference = n             

for third-order bright fringe , n = 3

= wavelength = 440 nm

so Path difference = 3 x 440 nm = 1320 nm = 1.32 m

2. i = angle of incidence = angle of reflection = 60    (given)

refractive index of air = n₁ = 1

refractive index of water = n₂ = 1.33

let the angle of refraction = r

using snell's law

n₁ sini = n₂ sinr

(1 ) sin60 = (1.33) sinr

sinr = 0.651

r = sin^-1(0.651)

r = 40.62 degree