Wave refraction

Articles about Wave refraction

One characteristic of waves is refraction. Refraction occurs when a wave that originally traveled through one medium enters a different medium. For example, a sound wave initially moves through the air and then encounters a wall, some sound waves are reflected by the wall, some are refracted by the wall. Refraction means that sound waves are absorbed or transmitted in the wall, but the direction of propagation changes. The change in the direction of propagation occurs because the speed of the sound wave changes when it enters a different medium from the previous medium.

The angle between the incident ray and the normal is called the angle of incidence, while the angle between the refracted ray and the normal is called the angle of refraction.

If the speed of the wave increases when it enters a new medium, the angle of refraction also increases. Conversely, if the speed of the wave decreases when it enters a new medium, then the angle of refraction also decreases.

For example, a sound wave moves from air into water, so the speed of the sound wave decreases. Or earthquake waves travel from the ground to the rocks, reducing the speed of the waves. Conversely, the speed of the wave increases when moving from a denser medium to a less dense medium.

Have you ever played at the beach? If you pay close attention, the direction of the sea waves in the middle of the ocean doesn’t always go to the beach.

But as it gets closer to the beach, the direction of the sea waves is getting parallel to the beach. This happens because of the refraction of sea waves.

The Law of Refraction

During the same time interval, wavefront 1 moves a distance of l₁ = v₁ t and wavefront 2 moves a distance of l₂ = v₂ t. Where v₁ is the speed of the wave in medium 1, such as air, and v₂, is the speed of the wave in medium 2, such as water.

P is the same, so both formulas simplify to:

Conceptual questions and answer about Wave refraction

1. What is wave refraction? Wave refraction is the change in direction of a wave due to a change in its transmission medium and speed.
2. What is Snell’s law and how is it related to wave refraction? Snell’s law, also known as the law of refraction, describes how the angle of incidence of a wave is related to its angle of refraction. The law is given as n₁sinθ₁ = n₂sinθ₂, where n is the refractive index and θ is the angle of the wave relative to the normal.
3. What is the refractive index? The refractive index (n) of a medium is a measure of how much it can bend or refract light. It’s the ratio of the speed of light in a vacuum (c) to the speed of light in that medium (v). It’s calculated using the formula: n = c/v.
4. How does wave speed affect refraction? If a wave enters a medium where its speed is slower, the wave bends towards the normal line (the line perpendicular to the interface). If it enters a faster medium, it bends away from the normal line.
5. What happens when a wave hits a boundary at a 90-degree angle? If a wave strikes the boundary at a 90-degree angle (perpendicular), it continues through the medium without bending. This is because the angle of incidence and the angle of refraction are both 0°.

6. What is total internal reflection? Total internal reflection occurs when a wave traveling in a medium hits the boundary at an angle greater than the so-called critical angle with respect to the normal to the surface. If this happens, the wave is completely reflected and no refraction occurs.