Laws of refraction
Explore how light behaves during reflection and refraction, and experiment with different angles and materials to see their effects using our interactive simulator.
Laws of refraction
Ever wondered what happens to a light ray when it enters a medium with a different refractive index? When light encounters such a medium, it undergoes both refraction and reflection. Our simulator vividly illustrates this optical phenomenon, allowing you to explore the intricacies of refraction.
Dive into our simulator below and experiment with the controls. Adjust the refractive indices and the angle of incidence, and observe the resulting angles of reflection and refraction. Start simulating now!
\( n_{1} *sin (θ_{1})=n_{2} *sin (θ_{2})\)
Mathematical description
Snell’s Law describes the relationship between the angles of incidence and refraction when light passes between two media.
where:
- \( n_{1} (n_{2}) \) is the refractive index of incident(refracted) ray medium.
- \( \theta_{1}(\theta_{2}) \) is the incident(refracted) angle from normal.
Tutorial video
Take a quick spin through our simulator!
FAQs on Laws of refraction
Qus 1. What is refraction?
Refraction is the bending of light as it passes from one medium to another with different densities, causing a change in its speed.
Qus 2. What are the laws of refraction?
There are two laws of refractions:
- The first law states that the incident ray, the refracted ray, and the normal to the interface of two media all lie in the same plane.
- The second law, or Snell’s law, states that the ratio of the sines of the angles of incidence and refraction is constant and is equal to the ratio of the indices of refraction of the two media.
Qus 3. What is Snell's Law?
Snell’s Law is a formula used to describe the relationship between the angles of incidence and refraction and the refractive indices of the two media: \( n_{1} *sin (θ_{1})=n_{2} *sin (θ_{2}). \)
Qus 4. What is the refractive index?
The refractive index, denoted as “n“, is a dimensionless number that describes how light propagates through a medium. It is defined as the ratio of the speed of light in a vacuum to the speed of light in the medium:
n= c/v
where:
- c is the speed of light in a vacuum ,
- v is the speed of light in the medium.
The refractive index indicates how much the light slows down and bends when entering the medium. For example, the refractive index of water is about 1.33, meaning light travels 1.33 times slower in water than in a vacuum. The refractive index can also affect the angle at which light is refracted when it enters a different medium, as described by Snell’s Law.
Different materials have different refractive indices, which determine how much the light will bend when passing through them.
Qus 5. What are some instances when we see refraction in our daily life?
In our day-to-day life, we see refraction as optical illusions.
Refraction causes optical illusions because it changes the direction of light rays as they pass through different media with varying densities. This bending of light can make objects appear distorted, shifted, or in different positions than they actually are. Here are a few examples:
Mirages: In a desert or on a hot road, the air near the surface is much hotter (and thus less dense) than the air above it. Light from the sky refracts as it passes through these layers of air, creating the illusion of water on the ground.
Bent Objects in Water: When you place a straight object like a stick or straw into water at an angle, it appears bent at the water’s surface. This is because light rays from the submerged part of the object bend as they move from the water (higher density) to the air (lower density).
Fish in a Pond: Fish and other objects underwater appear closer to the surface than they actually are because light rays bend away from the normal as they exit the water into the air.
Magnifying Lens: Refraction is used in lenses to focus or spread out light rays, enabling the creation of images in devices such as glasses, cameras, and microscopes.
These illusions occur because our brains interpret light as traveling in straight lines, so when light bends, the perceived position of objects changes.
Qus 6. Why do light rays bend when they enter a different medium?
Light rays bend, or refract, when they enter a different medium due to a change in their speed. This change in speed is caused by the difference in optical density between the two media. The optical density of a medium is related to how much it slows down the light.
Here’s a more detailed explanation:
When light travels from a less dense medium (like air) to a more dense medium (like water), it slows down. As it slows down, it bends towards the normal (an imaginary line perpendicular to the surface at the point of incidence).
Conversely, when light travels from a more dense medium to a less dense medium, it speeds up and bends away from the normal
The degree of bending depends on the ratio of the refractive indices of the two media. If the refractive index of the second medium is higher than that of the first, the light ray bends towards the normal. If the refractive index of the second medium is lower, the light ray bends away from the normal.
Qus 7. What is total internal reflection?
Total internal reflection can be thought of an extreme example of refraction. It is the optical phenomena where light rays traveling from a denser to a rarer medium are reflected back at the interface of two mediums. Total internal reflection occurs in two conditions
- when light travels from a denser medium to a less dense medium
- when the angle of incidence exceeds the critical angle, causing the light to be completely reflected within the denser medium.
Critical angle is the angle of incidence at which light is refracted along the boundary, causing the refracted ray to travel along the interface between two media.
