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Refraction of Light: When light moves from one substance to another and crosses the boundary between the two substances head-on, it will travel straight through with no change in direction (perpendicular, or a 90-degree angle of incidence). If the light strikes the border at any other angle, it will be bent or refracted, with the degree of refraction increasing as the beam approaches the boundary at a greater angle. A beam of light striking water vertically, for example, will not be refracted; nevertheless, if the beam enters the water at a tiny angle, it will be refracted to a minor degree. The light will refract in proportion to the entry angle if the angle of the beam is increased even more. The ratio between the angle at which light crosses the media interface and the angle created after refraction is a fairly exact feature of the substance that produces the refraction effect, as early scientists discovered.
The information about refraction of light from various physics-related articles are available here. Refraction of light and its general concept are important topics in physics. Students who want to flourish in physics need to be well known about refraction and refraction of light to get deep knowledge about it to do well on their exams. The definition, laws, uses and applications are provided here to assist students in effectively understanding the respective topic. Continue to visit our website for additional physics help.
Overview of Refraction of Light
When visible light moves from one substance or medium to another, the light waves may experience refraction, which manifests as bending or change in direction of the light. When light flows from one medium to another, refraction occurs only when the index of refraction of the two materials differs.
Refraction is responsible for a number of well-known phenomena, including the apparent bending of an object partially submerged in water and the mirages seen in a hot, sandy desert. Visible light refraction is another key property of lenses that allows them to focus a beam of light onto a single point. The path of travel followed by a beam of light is referred to as the refraction of light. You’ve all noticed how objects appear to change direction when viewed through glass.
Refraction of Light (Ray Optics III) – Video
The direction of change is determined by the thickness of the glass and the surrounding environment. This effect can also be noticed in pure water. The path of a light beam travelling from one medium to another is deflected from the straight line it usually follows.
Due to the interface of two media of differing densities, the frequency of incident light remains constant as the wavelength changes. As a result, the direction of light bends away from the regular path of passage for light.
The direction of a light ray changes when it strikes the surface separating two media is called refraction of light. We can say that the speed of light is maximum or highest in a vacuum. In any medium, light travels at a slower rate.
At the interface of the two separate media, the direction of light changes as a result of this. The frequency of incident light remains constant, while its speed and wavelength vary. Whenever a light beam approaches a denser medium, it bends closer to the normal, but in a lighter medium, it moves away from the normal.
Laws of Refraction
There are two laws:
- At the point of incidence, the incident ray, refracted ray, and normal to the refracting surface all belong to the same plane.
- The ratio of the sine of the angle of incidence (angle between the incident ray and normal) to the sine of the angle of refraction (angle between refracted ray and normal) is constant, according to Snell’s Law. The constant is affected by the two mediums as well as the incident light’s wavelength.
Refractive Index
The refractive index, commonly known as the index of refraction, is a measurement of how quickly light passes through a material.
The refractive index does not have a dimension. The refractive index of a material is the ratio of the speed of light in a vacuum (c) to the speed of light in the medium (v). If n is used to represent the refractive index of a medium, the following formula is used to calculate it:
n=c/v
The light ray changes direction or bends at the junction separating the two media depending on the refractive index of the medium. When light passes from one medium to another with a higher refractive index, it bends more toward the normal, and when it travels from one medium to another with a lower refractive index, it bends away from the normal.
Effects of Refraction of Light in Nature
- The refraction of sunlight by the surfaces of water droplets causes a rainbow to emerge after a shower.
- When the sun rises, the sun’s light refracts through the Earth’s atmosphere and reaches our eyes before the sun crosses the horizon. Similarly, light rays from the sun are refracted and reach us after sunset. As a result, the sunrise is a little earlier and the sunset is later.
- The apparent position of faraway stars varies gradually due to the Earth’s heterogeneous atmosphere, generating twinkling.
Application of Refraction of Light
- Lenses are transparent objects that use refraction to focus light. Cameras and binoculars both make use of lenses.
- Different telescopes are employed in cosmology to explore faraway objects in the universe. Microscopes are commonly employed in science to examine extremely minute objects that would otherwise be invisible to the naked eye. Refraction is used in these optical equipment to magnify images of distant or small objects.
- Prisms are transparent wedge-shaped devices that are commonly employed as optical filters to extract a specific wavelength. Various wavelengths of light propagate at different speeds in a material, causing them to refract at different angles. Dispersion is the term for this occurrence (observed in prisms).
- Optical fibres, which are utilized for communication with minimal energy dissipation, are an essential use of refraction.
Also read: Optical Fibres and its Types
Frequently Asked Questions (FAQs)
What is Refraction of Light?
At the interface of two mediums, the direction of a light ray changes. The refraction of light is the name for this event. In different media, light travels at different speeds. Refraction occurs as a result of this. The light ray shifts towards the normal when refracting from a rarer to a denser medium, but away from the normal when refracting from a denser to a rarer medium.
What are the properties of Light Refraction?
During refraction, the frequency of light remains constant while the speed and wavelength change. At the incidence point, the incident ray refracted ray, and normal to the boundary are all on the same plane. The relative refractive index of the second medium with regard to the first is equal to the ratio of the sine of the incident angle to the sine of the refracted angle.
What are the different types of refraction?
The relative refractive index is used to determine the degree of refraction in various materials. The refractive index of light travelling from a rarer media like air to a denser medium like the glass is always larger than one. The angle of reflection is always less than the angle of incidence in such a circumstance. When the light goes from a denser media to a rarer medium, the relative refractive index inverts to a value less than one.
Why does light refract as it passes through one medium and into another?
Light has a constant speed of movement that is maintained even when it travels through a single medium. In a vacuum, the speed of light is approximately 300000 km per second. When the density of the medium varies, however, this speed can shift. Denser media, such as glass or water, allow light to travel more slowly. Because the frequency remains constant as the speed slows, the wavelength varies, causing the incident light to deviate from its regular path of passage. While deviating from the incident light, it follows Snell's law of refraction.
