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Films

Thin-Film optics is the study of optics that deals with thin structured layers of different material. In order to exhibit thin-film optics, the thickness of the layers of material must be on the order of the wavelengths of visible light. This is able 500nm. The layers have reflective properties due to light wave interference and the difference in refractive index between the layers, the air and the substrate. These effects alter the way the optic reflects and transmits light. It is called thin-film interference.

Thin film layers can be achieved through the deposition of one or more thin layers of material onto a substrate in manufacturing. Often this is achieved by using physical vapor deposition process or a chemical process. Thin films are used to create optical coating used in everyday life such as low emissivity panes of glass, anti-reflective coatings on glasses and mirrors.

Thin-film layers can be observed in the natural world. Their effects produce colors from soap bubbles and oil slicks. Thin-film layers also can be seen in the structural coloration of some animals. Iridescent colors that were once thought to result from planar laws turn out to result from more complex period photonic crystal structures in thin-film layers. 

Image and blurred region size

A radiograph is made of an object with a width of 3 mm using an x-ray tube with a 2 mm focal spot at a source-to-film distance of 100 cm. The object being imaged is 15 cm from the film. Find the size of the image and the size of the blurred region at its edges.

Screen position from the movie projector

A movie projector at the theater uses a simple lens. If the lens has a focal length of 20cm, and the object--the film is placed 22cm from the lens, how far away should the screen be placed for good focus?

In a thin water

In a thin water film in air, there are exactly 80 wavelengths of blue light inside the film. the reflected light from the two surfaces of the film will a. be deficent in blue light b. be brightest in the blue part of the specrtum c. have the normal amount of blue light d. none of the above

Capacitance of a parallel plate capacitor with dielectric.

17.68) A capacitor is made from two parallel conducting plates, each with an area of 860 squared. The plates are separated by a dielectric film 0.250 mm thick. Measurements show that the potential difference between the plates is 185 V when the charge on the plates is 1.75 uC. (a) What is the capacitance of the capacitor? (b) Wh