Reflection Refraction Diffraction Interference

What is Reflection, Refraction and Diffraction?

​Reflection of light

Law of reflection

The angle of incidence (i) is equal to the angle of reflection (r)

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Virtual image

A virtual image is an upright image that is achieved where the rays seem to diverge. A virtual image is produced with the help of a diverging lens or a convex mirror. A virtual image is found by tracing real rays that emerge from an optical device backwards to perceived or apparent origins of ray divergences.

​Refraction of light

Refraction is the redirection of a wave as it passes from one medium to another.

This speed change usually causes the wave to change direction.

Water waves slow down as they pass over from a deeper to a shallower region.

Light slows down as it passes from air into glass, perspex or water.

​Refraction of light on a plane surface

​Light bends toward the normal. The angle of refraction is less than the angle of incidence.

​This is light bend from a more to less optical dense transition (water to air). Light bends away from the normal. The angle of refraction is greater than the angle of incidence.

Diffraction

Diffraction of sound

Diffraction is the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a secondary source of the propagating wave