Thin film interference Definition and 69 Threads

Hi everyone! Here's the problem related to thin film interference. I mean, it's not quite a problem. I've been looking for the formulae related to this type of interference and fount two different things in two different textbooks. It's the formula for the optical difference of the wave...

Homework Statement A thin film of MgF2 with n = 1.38 coats a piece of glass. Constructive interference is observed for the reflection of light with wavelengths of 500 nm and 625 nm. Part A - What is the thinnest film for which this can occur? Homework Equations t = lambda/2n *(m + .5)...

Homework Statement An oil film (index of refraction no = 1.48) floating on water (index of refraction nw = 1.33) is illuminated from above by white light at normal incidence. The film is 360.0 nm thick. What is the longest visible wavelength that will be strongly reflected? What is...

For thin film interference, I was wondering how you know what the value of m is for the equations: 2nt/λ=m (destructive) 2nt/λ -1/2=m (constructive)

My question concerns thin films of varying thickness. I have a basic understanding of thin film interference, and understand the effects of thickness on wavelength, and that with increasing thickness color fringes will be evident. I understand that the color fringes come from: n*t = m*\lambda...

Homework Statement A pair of slits separated by d = 1.30 mm is illuminated with light of l = 610 nm wavelength and falls on a screen L = 2.00 m away. A piece of glass with index of refraction n = 2.2 is placed at one slit. If the maxima shift is Dx/2, and falls on a minimum, what was the...

Hey guys, I was wondering if someone could explain to me when Thin Film Interference will produce constructive/destructive interference. I think I might understand it, but I'm not 100% sure and I have a test coming up soon. Any help would be great! Ok, so I know we have the equation: 2t =...

A thin film is put on the surface of glass, with indexes of refraction of x and y respectively. If light, with wavelength L in air, is reflected from the 2 sides of the film, to interfere constructively, what is the minimum thickness required. The question is stated just like that, so I...

Homework Statement One of the beams of an interferometer passes through a small glass container containing a cavity 1.30 cm deep. When a gas is allowed to slowly fill thr container, a total of 236 dark fringes are counted to move past a reference line. The light used has a wavelength of 610...

Hi - I'm having trouble with the following problem: A mixture of yellow light (wavelength = 574 nm in vacuum) and violet light (wavelength = 418 nm in vacuum) falls perpendicularly on a film of gasoline that is floating on a puddle of water. For both wavelengths, the refractive index of...

Newton's rings are observed in monochromatic light reflected from the air gap between a convex spherical piece of glass (radius of curvature R) and a plane slap of glass. The two pieces are in contact in the centre. (b) Show that the dark fringes have radii given approximately by r=...

Two oblong pieces of plane glass are separated from each other by a thin sheet of cellophane and held together with rubber bands, as shown in figure(I provided a website for the figure below), where the amount of separation is much exaggerated. If you place a "sodium vapor lam" vertically above...

I have observed puddles of oil on the pavement with swirling colours more often on overcast days than sunny days. Does the phenonmenon of thin film interference work better with diffuse/scattered light than light coming directly from a source? Or, is it a question of light incident at an oblique...

My professor gave the equation: 2t + \frac{\lambda}{2} = (m + \frac{1}{2})\lambda How did he derive this..where does it come from?

There's two problems I can't seem to figure out... I sort of got the answer, except I used m as 28 instead of 27. So my question is why are you suppose to use m as 27 to multiply instead of 28? Also What do they mean by incident normally, is it like striking the glass at a right angel? and...

A physicist wishes to deposit a thin film on both sides of a glass (with index of refraction 1.50) window to reduce reflected light of wavelength 532nm to 0% In order to achieve 100% destructive interference for light reflectedo ff of the air /thing film inteference and the light reflected...

A thin film of oil (n = 1.26) is located on a smooth, wet pavement. When viewed perpendicular to the pavement, the film appears to be predominantly red (640 nm) and has no component of wavelength 512 nm. How thick is the oil film? I'm getting confused by the use of two wavelengths in this...

A student diving in a swimming pool (filled with water with index of refraction 1.33) creates thin films of air. Viewed underwater, what are the first two non-zero thicknesses of an air film for which there will be constructive interference for reflection off the surfaces of the bubble for...

Please help: Two rectangular pieces of plane glass are laid one upon the other on a table. A thin strip of paper is placed between them at one edge so that a very thin wedge of air is formed. The plates are illuminated at normal incidence by 546-nm light from a mercury-vapor lamp...