What is the minimum thickness of a thin film for maximum light reflection?

AI Thread Summary
The discussion focuses on calculating the minimum thickness of a thin film for optimal light reflection, involving a glass plate coated with a transparent film. Key calculations include determining the frequency of monochromatic light with a wavelength of 6.0 X 10-7 meters in air, and its wavelength within the thin film. The minimum thickness for minimum reflected intensity is derived, alongside the minimum nonzero thickness for maximum intensity. These calculations are essential for understanding interference effects in thin films. The results highlight the relationship between film thickness and light behavior at interfaces.
Liquefaction
Messages
1
Reaction score
0
1984 PHYSICS B WAVES

The surface of a glass plate (index of refraction n3 = 1.50) is coated with a transparent thin film (index of refraction n2 = 1.25). A beam of monochromatic light of wavelength 6.0 X 10-7 meter traveling in air (index of refraction n1 = 1.00) is incident normally on surface S1 as shown above. The beam is partially transmitted and partially reflected.

a) Calculate the frequency of the light.

b) Calculate the wavelength of the light in the thin film.

The beam of light in the film is then partially reflected and partially transmitted at surface S2·

c) Calculate the minimum thickness d1 of the film such that the resultant intensity of the light reflected back into the air is a minimum.

d) Calculate the minimum nonzero thickness d2 of the film such that the resultant intensity of the light reflected back into the air Is a maximum.
 
Physics news on Phys.org
You're going to have to show some of your own work first.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top