- #1
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- 199
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Homework Statement
White light is incident normally on a thin soap film (n = 1.33) suspended in air.
1. What is the minimum thickness of the soap film that will constructively reflect light of wavelength 477 nm?
2. What is the next minimum thickness of the soap film that will constructively reflect light of wavelength 477 nm?
Homework Equations
DONT NEED NONE
The Attempt at a Solution
for #1 i found the answer is [itex]\frac{\frac{\lambda}{n}}{4}[/itex] so 89.66nm was the answer to this, but i don't know why i divided by 4. can someone give an equation/explanation of why i had to do this?
for #2 i have no idea but i foudn to get the right answer i just multiplied my answer for #1 by 3. so 86.99*3=269nm.