# Refraction of Light: Definition, Properties, Laws, and Its Application

Refraction of light is – Maybe you have heard a glimpse of the explanation of the refraction of light. Usually when I was at school, learning material about light refraction was indeed taught.

Rainbow is one example of a natural event that can occur as a result of light refraction. Simply put, refraction of light is an event of deflection of the direction of light when it passes through two substances or mediums. Which when this process occurs there is also a different optical speed of light.

Refraction of light can also occur due to the speed of light when it enters a different medium. Because this can make the speed of light change and cause light waves to bend.

The light that was in the air will enter the water and can make the light bend. This bending event of light entering a different medium is often referred to as refraction or reflection.

## Definition of Refraction of Light

The first thing we will learn together is the meaning of light refraction. Previously, it was explained briefly about what light refraction is. But at this point we will explain more deeply what is meant by refraction of light.

Refraction is an event of deflection of the direction of propagation of light that can occur when light passes through a boundary between two different mediums. Refraction events can occur when there is an incident ray and forms a certain angle the incident light is not perpendicular to the boundary or the angle of incidence is smaller than 900 to the boundary.

Meanwhile, light itself is an electromagnetic wave that propagates straight in all directions with a speed of 3 x 108 m/s and has a wavelength of around 380 to 750 nm. In physics, light is a package of particles called photons.

From these two explanations, an understanding can be drawn if light refraction is a process of bending light when the light beam passes through the boundary of two media with different refractive indices.

The refractive index of a material is the ratio of the speed of light in a vacuum to the speed of light in that material. Meanwhile, the relative refractive index is a comparison of the refractive indices of two different media.

The relative index of refraction of the second medium to the first medium is the ratio of the index of refraction between the second medium and the index of refraction of the first medium. The existence of this light refraction can cause an apparent depth and perfect reflection.

## Properties of Light

A light also has properties based on the direction of propagation. You can read more about some of the properties of light below.

### 1. Light Travels According to a Straight Line

The sun is the largest source of light on earth. Where the sun has straight rays. Because the propagation of light from the sun to the earth can cause day and night events.

As for examples of real events where the process of light propagating in a straight line is a solar eclipse and a lunar eclipse. Where the sunlight that is blocked by the moon can make some of the earth experience the dark side.

### 2. Light can propagate through clear objects

Objects that have clear or transparent properties can be penetrated by light. Objects that have colorless or transparent particles can be propagated by light more easily. This happens because clear or transparent objects can easily transmit the incoming light.

An example is the incident of light through a clear glass window. Where the window glass cannot block the coming of sunlight and can directly enter the house. We can even look outside the glass window because basically light can still penetrate outside the clear glass and be caught by our eyes.

### 3. Light Can Be Reflected

Light can be reflected by reflecting or emitting light from the surface of an object that was previously exposed to light. The nature of the reflection possessed by this light can be divided into two, namely regular reflection and diffuse or diffuse reflection.

In the process of regular reflection, the light rays will reflect in parallel. This is like when you play during the day with a mirror that is used to reflect light. When you point the mirror towards the light. Then the light can be reflected in all directions from the reflected light.

Meanwhile, diffuse or diffuse reflection is a reflection of light that occurs on an uneven surface. An example is the reflection of light on water, rocks, trees, asphalt and shoes. Mirrors also have the property of reflecting light and are divided into several types, namely flat mirrors, convex mirrors and concave mirrors.

### 4. Deflectable Light

Light can be refracted when it moves obliquely through mediums of different densities. An example is the light from the air will then pass through the water. Because of this, light will experience refraction and deflection in the medium.

The nature of light that can be refracted or deflected is also widely used in various kinds of optical devices. An example is when you see a pond that looks shallow because it has clear water, even though the pool may have a deeper depth than what you see above the surface.

Those are some of the properties of light. In addition to the four properties described above, light also has several other properties.

## Properties of Light Refraction

After knowing the nature of light in general. Next is about some of the properties in light refraction which you can read in full below.

### 1. Refraction of Light from a Loose Substance to a Dense Substance

The first property is the refraction of light from a sparse substance to a denser substance. Where this can happen when light is refracted from air to water. Air is a more tenuous medium than water, so light will be refracted close to the normal line.

### 2. Refraction of Light from a Dense Substance to a Loose Substance

The next property is the refraction of light from a denser substance to a more sparse substance. This condition can occur when light is refracted from glass to water. Glass has a denser medium than water. Therefore the light will be refracted away from the normal line.

Those are the two properties of light refraction that you can read in full.

## Causes of Refraction of Light

Refraction of light is a change in the direction of propagation of light when it moves from one medium to another that has a different optical density. The cause of the refraction of light will be divided into two types. The two types of causes for the occurrence of light are as follows.

When light comes from a medium that has a less dense density towards a denser medium, then the incoming light will be refracted towards the normal line. An example is when light comes through the air medium to the water.

When light comes from a denser medium to a more tenuous medium, the incident light will be refracted away from the normal line. An example is when light comes through the medium of water into the air.

## Light Refractive Index

Refraction of light can occur due to differences in the speed of light in the two media used. The speed of light in a medium that is smaller than the speed of light in a medium that is less dense.

Mathematically it can be formulated as follows.

Refractive index is never less than 1 (that is, n ³1)

## The Law of Light Refraction

Around 1621, a Dutch scientist named Willebrord Snell conducted an experiment to find the relationship between the angle of incidence and the angle of refraction. The results obtained from these experiments are called Snell’s law as explained below.

The incident ray, the normal and the refracted ray will lie in one plane.
The quotient of the sine of the incident angle with the sine of the angle of refraction is a fixed number or can be called the index of refraction.

When viewed mathematically, the quotient of the angle of incidence and the angle of refraction will be expressed as follows.

## The Application of Refraction of Light in Life

In everyday life there are several events of light refraction. What are the applications of refraction of light in everyday life? The following is a full explanation of this.

### 1. Perfect Bounce

Perfect reflection can occur when a beam of light comes from a dense medium or a large index of refraction to a less dense medium or a small index of refraction. The condition for perfect reflection is that the angle of incidence must be greater than the critical angle or angle of incidence that can produce a 90 degree angle of refraction.

This perfect reflection is usually used in the manufacturing process as well as in optics. Optical fiber is a type of cable that has such a high transmission power.

### 2. A pencil or straw that looks broken

Maybe you have personally conducted experiments using pencils or straws and water. Where when a pencil or straw is put into the water in a glass it will look like it is broken. This can happen because it is caused by differences in the medium through which light passes.

### 3. Seawater looks shallow

If you have ever been to the beach, maybe you have also seen sea water that is so shallow and want to swim in it. Even though the sea water is not shallow.

Sea water that can appear shallow is none other than because of the light that passes through two different mediums, namely from air to water. The principle used is almost the same as the pencil experiment which appears to break when it is placed in water.

### 4. Refraction in the lens

Lenses do have many benefits in this life. For example, lenses can be used in glasses, binoculars, lenses and microscopes. Did you know that the lens that is used to see objects beyond the limits of the human eye is due to the refraction of light that enters it.

The index of refraction between the lens medium and air is indeed different. Because of this, the lens can refract the light that enters it.

An example is for those who suffer from nearsightedness or farsightedness. After wearing glasses, they will be able to see more easily at normal distances. This is none other than because there are more formed by objects still falling on the retina.

Those are some applications of light refraction in everyday life. Maybe after reading a few examples of the application of light as above, it will be easier for you to know what forms of light refraction are in everyday life.

## Refraction of Light in the Lens

The lens is a clear object that is shaped in such a way as to refract or allow most of the light that passes through it. Currently there are two types of lenses that you can find easily, namely convex lenses or positive lenses and concave lenses or negative lenses.

You can read these two types of lenses in more detail in the review below.

### 1. Convex Lens or Positive Lens

A convex lens is also known as a converging lens or positive lens. Which convex lens has a thicker center than the edges.

Convex lenses are also divided into three types of lenses as explained below.

1. A double convex or biconvex lens is a lens with both surfaces having a convex shape.
2. A flat convex lens or plankonvex is a lens that has one convex lens shape and one flat lens shape.
3. A concave convex lens or convex concave lens is a lens with one convex and one concave surface.

It should be noted that a convex lens has properties like a concave lens. Therefore the image formed will be almost the same as a concave lens. For further explanation about this is as follows.

The real image is formed from the intersection of the refracted rays that gather. The real image on a convex lens occurs when the object is in space II and III.

A virtual image can form from the intersection of divergent or spreading rays of venom. A virtual image on a convex lens can occur if it is located in space I.

### 2. Concave Lens

A concave lens is also known as a diverging lens or negative lens. Where a concave lens is a lens that has a thinner center than the edges. It should also be noted that a concave lens has a property called diverging or being able to scatter light. The formation of an image on a concave lens has a focal point or focus which is expressed negatively.

Same with convex lenses, concave lenses are also divided into three types of lenses. The three types of lenses in a concave lens are as follows.

1. A double concave lens or biconcave lens is a lens with both concave surfaces.
2. A flat or planconcave concave lens is a lens with one concave surface and the other is flat.
3. A convex or convex concave lens is a lens with one concave and the other convex surface.

The special rays produced by a concave lens are as follows.

1. Rays coming parallel to the main axis of the lens will be refracted as if they were coming from the active focus point F1.
2. The incoming ray as if going to the passive focal point F2 will be refracted parallel to the main axis.
3. Rays will come to the optical center point O forwarded without refraction.

That’s a summary of the refraction of light . Sinaumed’s can read books related to Physics by visiting sinaumedia.com , so you have #MoreWithReading information.