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pinkberry
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Homework Statement
Light of wavelength 5000 angstroms is incident normally on a series of two transparent plastic disks separated by a distance large compared with the wavelength. If the index o refraction of the disks is n=1.5, what fraction of the light is transmitted? Neglect absorption, internal multiple reflections, and interference effects.
Homework Equations
T = 1+R
R = (n1-n2)/(n1+n2), where n is the index of refraction depending on the material
Itotal is proportional to |Etotal|^2 = Etot * (Etot*) where (Etot*) is the complex conjugate.
The Attempt at a Solution
R = (1-1.5)/(1+1.5) = -0.20: going from air to the disk1
Similar calculations for air to disk1, disk1 to air, air to disk2, and disk2 to air.
I tried to calculate Etotal as:
Etotal = -0.20*E0 + 0.20E0* e^(i*delta)
delta = 2kd = 2*(2pi/lambda)*d where d = thickness of the disc
but I am not given a thickness...
Am I missing an equation I need to use? Approaching this from the wrong angle?
Any advice would help! Thank you.