PHYSICS 7E Lecture 23: PHYSICS 7E - Lecture 23 - Interference
PHYSICS 7E - Lecture 23 - Interference
*Images from University Physics, Young & Freedman
Phase Shifts During Reflection
●A beam of light reflected by a material with index of refraction greater than that of the
material in which it is traveling, changes phase by or ½ cycle801 °
●Electromagnetic waves propagating in optical materials
●Mechanical waves propagating on ropes
Conditions of Constructive and Destructive Interferences
●Assuming small angle of view
○For constructive interference:
■nt m /2)λ m, , ...2 = ( + 1 = 0 1 2
○For destructive interference:
■nt λ m, , ...2 = m= 0 1 2
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PHYSICS 7E Full Course Notes
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Document Summary
A beam of light reflected by a material with index of refraction greater than that of the material in which it is traveling, changes phase by. A similar effect takes place when a shallowly curved piece of glass is placed on a flat one. When viewed from above, concentric circles appear that are called newton"s rings t. /2) r2 = r2 ( t 2 = 2 t2 2. The lens to be tested is placed on top of the master lens. If the two surfaces do not match, newton"s rings will appear, as in figure 35. 17 at the right. The purpose of the non-reflecting film is to cancel the reflected light. The michelson interferometer is used to make precise measurements of wavelengths and very small distances. General relativity predicts the existence of gravitational waves. In einstein"s theory, gravity is equivalent to a distortion of space. These distortions can then propagate through space and make things moving.
