1. Change in Speed:
* Light travels at different speeds in different mediums. For example, light travels faster in air than in water.
* When light enters a denser medium (like water) from a less dense one (like air), it slows down.
2. Change in Direction:
* The change in speed causes the light ray to bend at the boundary between the two mediums.
* The direction of bending depends on the angle of incidence (the angle at which the light ray hits the boundary) and the refractive indices of the two mediums.
* The light ray bends towards the normal (an imaginary line perpendicular to the surface) if the second medium is denser. It bends away from the normal if the second medium is less dense.
3. Snell's Law:
* Snell's Law describes the relationship between the angles of incidence and refraction, and the refractive indices of the two mediums:
* n₁sinθ₁ = n₂sinθ₂
* Where:
* n₁ and n₂ are the refractive indices of the first and second mediums, respectively.
* θ₁ and θ₂ are the angles of incidence and refraction, respectively.
Examples:
* A straw in a glass of water: The straw appears bent at the surface of the water because the light rays from the straw bend as they travel from water to air.
* A rainbow: Rainbows are formed when sunlight refracts through water droplets in the atmosphere.
In summary:
* When a ray of light slows down as it enters a new medium at an angle, it bends.
* The direction of bending depends on the angle of incidence and the refractive indices of the two mediums.
* This phenomenon is called refraction and is described by Snell's Law.
