Let's discuss the concepts related to Optics and Diffraction. Explore more from Physics here. Learn now! Start Now. Diffraction : It refers to various phenomena that occur when a wave encounters an obstacle or a slit. Example: The rainbow pattern found on a CD. Get Started for Free Download App. More Diffraction Questions Q1. The optical phenomenon that is primarily responsible for the observation of rainbow on a rainy day is.
Grating are used in connection with:. Some of the sound from music in another room will pass through a wall. Low frequency notes usually travel through the wall material easier than high frequency notes. Radio and television electromagnetic waves pass through the walls in your house to reach the device's antenna. Light passes through some materials such as glass, but it is not transmitted in many other materials. Sound usually travels faster in denser material. Sound in water is faster than in air.
On the other hand, the speed of light is slower in denser materials. The speed of light in glass is slower than in air. When a wave is transmitted through a material on an angle, its direction is changed. You can see that when light goes through water at an angle. That phenomenon is called refraction. Some materials absorb better than others. This characteristic is observed for water waves and sound waves. It is also observed for light waves. Light, like any wave, follows the law of reflection when bouncing off surfaces.
The reflection of light waves will be discussed in more detail in Unit 13 of The Physics Classroom. For now, it is enough to say that the reflective behavior of light provides evidence for the wavelike nature of light. All waves are known to undergo refraction when they pass from one medium to another medium. That is, when a wavefront crosses the boundary between two media, the direction that the wavefront is moving undergoes a sudden change; the path is "bent.
First, the direction of "bending" is dependent upon the relative speed of the two media. A wave will bend one way when it passes from a medium in which it travels slowly into a medium in which it travels fast; and if moving from a fast medium to a slow medium , the wavefront will bend in the opposite direction.
Second, the amount of bending is dependent upon the actual speeds of the two media on each side of the boundary. The amount of bending is a measurable behavior that follows distinct mathematical equations. These equations are based upon the speeds of the wave in the two media and the angles at which the wave approaches and departs from the boundary. Light, like any wave, is known to refract as it passes from one medium into another medium.
In fact, a study of the refraction of light reveals that its refractive behavior follows the same conceptual and mathematical rules that govern the refractive behavior of other waves such as water waves and sound waves. The refraction of light waves will be discussed in more detail in Unit 14 of The Physics Classroom Tutorial.
For now, it is enough to say that the refractive behavior of light provides evidence for the wavelike nature of light. Reflection involves a change in direction of waves when they bounce off a barrier. It is most pronounced when a light wave strikes an object with a size comparable to its own wavelength. An instrument called a spectrometer uses diffraction to separate light into a range of wavelengths—a spectrum.
In the case of visible light, the separation of wavelengths through diffraction results in a rainbow. A spectrometer uses diffraction and the subsequent interference of light from slits or gratings to separate wavelengths.
Faint peaks of energy at specific wavelengths can then be detected and recorded. A graph of these data is called a spectral signature. Patterns in a spectral signature help scientists identify the physical condition and composition of stellar and interstellar matter. Scattering occurs when light bounces off an object in a variety of directions.
The amount of scattering that takes place depends on the wavelength of the light and the size and structure of the object. The sky appears blue because of this scattering behavior. Light at shorter wavelengths—blue and violet—is scattered by nitrogen and oxygen as it passes through the atmosphere. Longer wavelengths of light—red and yellow—transmit through the atmosphere. This scattering of light at shorter wavelengths illuminates the skies with light from the blue and violet end of the visible spectrum.
Even though violet is scattered more than blue, the sky looks blue to us because our eyes are more sensitive to blue light. Aerosols in the atmosphere can also scatter light. Refraction is when light waves change direction as they pass from one medium to another.
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