Reflection, refraction, and diffraction are fundamental phenomena that occur when waves interact with different mediums or obstacles. These phenomena are commonly observed in various wave systems, such as light, sound, and water waves.
Reflection: Reflection refers to the bouncing back of a wave when it encounters a boundary between two different mediums. When a wave reaches a surface and cannot pass through, it is reflected, changing its direction. The angle of incidence (the angle between the incident wave and the normal to the surface) is equal to the angle of reflection (the angle between the reflected wave and the normal). The law of reflection governs this behavior.
Refraction: Refraction occurs when a wave passes from one medium to another and changes its direction and speed due to the change in the medium's properties, such as density or refractive index. When a wave enters a medium at an angle, it bends towards or away from the normal (a line perpendicular to the surface). This bending is due to the change in the wave's velocity, which causes it to change direction. The amount of bending depends on the angle of incidence and the properties of the two media involved.
Diffraction: Diffraction is the bending and spreading of waves as they encounter an obstacle or pass through a narrow opening. When waves encounter an obstruction or a slit comparable to their wavelength, they spread out into the region behind the obstacle or opening. This bending occurs because different parts of the wavefront behave as if they are point sources, creating interference patterns that result in bending and spreading. Diffraction is more pronounced when the size of the obstacle or opening is similar to or smaller than the wavelength of the wave.
These phenomena play crucial roles in various fields of science and technology. For example, they explain how light reflects off mirrors, how lenses refract light to form images, and how sound waves bend around corners or diffract through small openings. Understanding reflection, refraction, and diffraction helps in the design and application of technologies such as optics, telecommunications, and acoustics.