Refraction and reflection are two fundamental phenomena that describe how light interacts with surfaces and different media, and they differ in their underlying processes:
Reflection:
- Definition: Reflection is the bouncing back of light rays when they encounter a boundary between two different media, such as when light hits a mirror or a surface of water.
- Key Principle: The angle of incidence (the angle at which incoming light strikes the surface) equals the angle of reflection (the angle at which light bounces away from the surface). This is known as the law of reflection.
- Influencing Factors: The type of surface (smooth, rough), the angle of incidence, and the wavelength of light can affect reflection. For example, a smooth surface produces a clear reflection (specular reflection), while a rough surface causes a diffuse reflection.
Refraction:
- Definition: Refraction is the bending of light rays as they enter a medium with a different refractive index. This occurs when light travels from one medium (e.g., air) into another (e.g., water or glass).
- Key Principle: Refraction is governed by Snell's Law, which states that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant and is equal to the ratio of the refractive indices of the two media: \( n_1 \sin(\theta_1) = n_2 \sin(\theta_2) \), where \( n_1 \) and \( n_2 \) are the refractive indices, and \( \theta_1 \) and \( \theta_2 \) are the angles of incidence and refraction, respectively.
- Influencing Factors: The refractive index of both media, the wavelength of light, and the angle at which light enters the second medium.
Behavior of Refraction with Medium Density:
As light travels from a less dense medium (like air) to a denser medium (like water or glass), the angle of refraction decreases. This means that the refracted light bends toward the normal (the imaginary line perpendicular to the boundary between the two media). Conversely, when light exits a denser medium into a less dense medium, the angle of refraction increases, and the light bends away from the normal.
In summary:
- Reflection is the bouncing back of light, described by the law of reflection.
- Refraction is the bending of light as it enters a different medium, described by Snell's Law, with the angle of refraction decreasing as the medium gets denser.
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