Reflection and Refraction

When light flows through a transparent medium and bends, this is known as refraction. The optically rarer medium is one in which the velocity of light is higher, whereas the optically denser medium is one in which the velocity of light is lower. The refraction phenomenon is caused by differing light velocities in different media.

Reflection is the process of a ray of light bouncing back off a medium after impacting it. The fundamental principle of reflection is that the atoms of the reflecting surface absorb energy from the source and then radiate it as light beams. Because reflection takes place in the same medium, the refractive index will remain constant.

Reflection and refraction diagram:

According to the law of reflection:

• Same angle of incidence and  angle of reflection .

• On the same plane as the ray of incidence, the ray of reflection, and the normal drawn at the point of incidence, to the mirror.

According to the law of refraction,

• In any two media, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant.

• At the interface of any two mediums, the incident ray, refracted ray, and normal ray all lie in the same plane.

Types of Reflection:

Regular reflection, also known as specular reflection, happens when a light beam strikes a regular, polished, and smooth plane.

 Irregular reflection, also known as diffuse reflection, happens when a beam of light collides with a rough surface and reflects light in multiple directions.

 Absolute Refractive Index:

It’s the difference between the velocity of light in a vacuum and the velocity of light in a medium.

c/v = n

c being the vacuum speed of light .

v being medium speed of light .

The refractive index is a measurement of light velocity in a given material.

How is reflection and refraction different ?

Refractive index:

The index of refraction is a property of materials that is represented by the letter n. The speed of light in a vacuum divided by the speed of light in the substance is the index of refraction of a material. Light travels slower in a medium with a greater index of refraction. If the index of refraction of the second material, n2, is greater than the index of refraction of the first material, n1 (the light travels slower in the second material), it will bend towards the normal (n1 n2) .The light will bend away from the normal as it travels faster in the second material (n1 > n2) if the second material has a lower index of refraction . The angle of incidence is not equal to the angle of refraction, unlike reflection.Through the law of refraction, also known as Snell’s Law, the angle of incidence and angle of refraction are mathematically connected to the index of refraction of each substance.

Light through prism:

Prisms allow light to pass through them.When light enters a plastic or glass prism (typically a triangular prism), it refracts twice: once as it enters and once as it emerges. White light is refracted into all of its colours when it travels through a prism. When this light is projected onto a white surface, it appears to be a rainbow.White light is made up of a variety of colours that are separated at different angles. This is due to the fact that each colour refracts differently through the prism.

Important points:

• The differing velocity of light in various mediums causes refraction.

• Regular and irregular reflections are the two types of reflection.

• The velocity and wavelength of light rays change during refraction, but the frequency remains constant.

• The refractive index is a dimensionless measure of light velocity in a specific medium.

• In reflection, the angle of incidence and angle of reflection are the same, but not in refraction.

Conclusion:

There is a distinct difference between reflection and refraction, and it is critical to examine both words and comprehend their definitions. The property of a light that rebounds after striking a surface is known as reflection. Refraction is a phenomenon that occurs when light passes through a surface and undergoes some changes in appearance, as it does when it passes through a medium. The incident ray and the reflected ray are the two types of lights that are commonly used in this. Light energy is fantastic and has numerous applications.