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samdiah
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Homework Statement
Calculate the minimum thickness of a layer of manesium flouride(n=1.38) on flint glass (n=1.66) in a lens system, if light wavelength 5.50x10^2 nm in air undergoes destructive interference.
Given:
n1=1.38
n2=1.66
λ1=5.5*10^2 nm
Homework Equations
Δx=L(λ/2t)
n2/n1 = λ1/λ2
The Attempt at a Solution
Destructive interference is at λ/4, 3λ/4, 5λ/4 ...
So the λ in flint flass is λ2=(n1*λ)/n2
= 4.57 * 10^-7
Therefore the shortest thicknss should be λ/4
4.57*10^-7/4
1.14*10^-7
The answer however is wrong the answer is suppose to be 199 nm.
Can someone please help! Thanku