Reflection, Refraction, And Diffraction of Light Waves - SS3 Physics Lesson Note

Light waves can exhibit several different behaviours when they encounter a boundary or an obstacle. The three most common behaviours are reflection, refraction, and diffraction.

Reflection: Reflection occurs when light waves bounce off a surface and change direction. The angle of incidence, or the angle at which the light wave hits the surface, is equal to the angle of reflection, or the angle at which the light wave bounces off the surface. This behaviour is responsible for the way we see ourselves and our surroundings in mirrors, as well as for the reflection of light by other surfaces, such as water, glass, or metal.

Refraction: Refraction occurs when light waves pass through a boundary between two different mediums, such as air and water, and change direction. The change in direction is caused by a change in the speed of light as it passes through a different medium. This behavior is responsible for the bending of light that we see when we look at objects through lenses, such as glasses or telescopes.

Diffraction: Diffraction occurs when light waves bend around an obstacle, such as a small opening or a corner. This behaviour is responsible for the patterns of light and dark that we see when light passes through narrow openings, such as a pinhole camera or a diffraction grating. Diffraction is also responsible for the way sound waves can bend around corners or through small openings, such as when we hear someone speaking in another room.

These behaviors of light waves have important practical applications in many fields, including optics, astronomy, and medicine. Understanding and controlling these behaviors is essential for designing and building a wide range of devices, such as mirrors, lenses, microscopes, telescopes, and cameras, as well as for developing new technologies for medical imaging and communication.