Share
Two parallel slits are illuminated by light composed of two wavelengths, one of which is 657 nm. On a viewing screen, the light whose wavele
Question
Two parallel slits are illuminated by light composed of two wavelengths, one of which is 657 nm. On a viewing screen, the light whose wavelength is known produces its third dark fringe at the same place where the light whose wavelength is unknown produces its fourth-order bright fringe. The fringes are counted relative to the central or zeroth-order bright fringe. What is the unknown wavelength
in progress
0
Physics
4 years
2021-08-06T00:53:29+00:00
2021-08-06T00:53:29+00:00 1 Answers
14 views
0
Answers ( )
Answer:
λ = 5.75 10⁻⁷ mm
Explanation:
This is a slit interference exercise, we analyze each wavelength separately
λ = 657 nm indicate that the third dark pattern
a sin θ = (m + ½) lam
a sin θ = (3 + ½) 657 10⁻⁹
a sin θ = 2299.5 10⁻⁹ nm
for the other wavelength in the same place we have m = 4 bright
a sin θ = m lam
we substitute
2299.5 10⁻⁹ = 4 λ
λ =
λ = 5.75 10⁻⁷ mm