# Physics

46. A thin film of oil with a thickness of 90 nm rests on top of a pool of water. When white light incident on the film is reflected, what colors are seen? The refractive index of the oil is noil = 1.45.

This is my best attempt, just wondering if I was right. Any help would be appreciated.
2d = (m + ½)(λ /noil) (m = 0, assuming the minimum thickness)
(n air < n oil > n water) → the wave is inverted on the first reflection and not on the second reflection
[d = λ/4(noil) ] → 90nm = λ/4(1.45)
λ = 522 nm
According to wavelengths of visible light: Green = 520 - 565 nm

1. 👍
2. 👎
3. 👁

## Similar Questions

1. ### Fluid Mechanics

The kinematic viscosity of oil of specific gravity .8 is .0005 .This oil is used for lubrication of shaft of diameter .4 m and rotates at 190 rpm. Calculate the power lost in the bearing for a sleeve length of 90mm. The thickness

2. ### Physics

1. A cylindrical disk of wood weighing 45.0N and having a diameter of 30.0 cm floats on a cylinder of oil of density 0.850 g/cm3. The cylinder of oil is 75.0 cm deep and has the same diameter of the wood. (a) What is the gauge

3. ### Solar Energy Help ASAP

In the figure below the absorption coefficient as a function of the wavelength for several semiconductor materials is presented. Let's consider monochromatic light of photons with energy of Eph=1.55eV that incidents a film with

4. ### Science

A drop of oil of volume 10^10m spread out on water to make a circular film of radius 10^1m. What is the thickness of the film

1. ### Math

A fuel oil tank is an upright cylinder, buried so that its circular top 12 feet beneath ground level. The tank has a radius of 6 feet and is 18 feet high, although the current oil level is only 13 feet deep. Calculate the work

2. ### CAL-Help on dr/dt

A circular oil slick of uniform thickness is caused by a spill of 1 cubic meter of oil. The thickness of the oil is decreasing at the rate of 0.1 cm/hr as the slick spreads. (Note: 1 cm = 0.01 m.) At what rate is the radius of the

3. ### Physics

an open tank contains a layer of oil floating on top of a layer of water (of density 1000 kg/m3) that is 3.0 m thick, as shown. What must be the thickness of the oil layer if the gauge pressure at the bottom of the tank is to be

4. ### Physics

A drop of oil of 10^10m spread out on water to make a circular film of radius 10^1m. What is the thickness of the film.

1. ### integral calculus

A cylindrical tank of radius 3 ft length 8 ft is laid out horizontally .The tank is half full of oil that weighs 60 pounds per cubic foot. a.)determine the work done in pumping out oil to the top of the tank. b.)determine the work

2. ### physics

Accomplished silver workers in India can pound silver into incredibly thin sheets, as thin as 3.00 x 10-7 m (about one hundredth of the thickness of a sheet of paper). Find the area of such a sheet that can be formed from 3.70 kg

3. ### Calculus

An oil tank in the shape of a right circular cylinder, with height 30 meters and a radius of 5 meters is two-thirds full of oil. How much work is required to pump all of the oil over the top of the tank? (The density of oil is 820

4. ### Physics

A puddle of water (n = 1.33) is covered with a very thin layer of light oil (n = 1.20). What is the minimum thickness the oil in the region that does not reflect light with a wavelength of 550 nm?