Indirect light is the light obtained by a natural or an artificial source of light that tends to reach a particular place or person indirectly. The indirect propagation of light occurs when the rays of light bounce off the surface of an object. The indirect light generally has lower intensity as compared to the direct light obtained from the source of light. This is because of the reflection, refraction, diffusion, and dispersion of the radiations. Indirect light leads to the formation of light-coloured or partial shade of opaque objects. Various other terms used for indirect light include bright indirect light, medium indirect light, moderate light, low light, etc. The intensity of the indirect light can be increased up to a significant value by adding mirrors in the surroundings or by painting the walls and roof of the premises with white colour. The application of indirect light sources can be easily observed in restaurants and cafe’s that have ambient dimmed light.
Examples of Indirect Light
There are a number of indirect sources of light present around us. Some of them are listed below:
1. Sunlight
Sunlight that reaches us is a prominent example of indirect light in real life. The rays of natural light received from the sun tend to travel in straight lines until they are obstructed by an object present between its path of propagation. When such light radiations strike the rigid surface of objects such as tables, windows, curtains, etc. they tend to undergo refraction, reflection, diffusion, dispersion, and various other related phenomena. This implies that the light we obtain from the sun does not reach us directly, but instead it follows an indirect path of propagation. The reflection and refraction of light due to the obstacles reduce the intensity of the light by a significant value.
2. Moonlight
Moon does not have a light of its own. The light rays from the sun tend to bounce off the surface of the moon and get radiated in the surroundings. The colour of the moon during the lunar eclipse appears to be red due to the indirect sunlight reflected, refracted, and scattered by the earth’s atmosphere. This phenomenon forms yet another example of indirect light present around us.
3. Light through the Curtains
The light that tends to pass through the blinds or the curtains before reaching the observer or any particular area is yet another example of indirect light. Indirect light gets partially filtered due to the curtain present in between the path of propagation of the light.
4. LED Strips
LED is an acronym for light emission diode. An LED strip typically consists of a number of coloured or uncoloured light-emitting diodes. Such strips are generally fixed on the walls or boundaries of a room and are used for decorative purposes. The light radiated by the LED strips tends to spread and undergo multiple reflections. The reflected, scattered, refracted, or diffused LED light radiations can be used to illuminate the objects that are present in the room at a distance, which is why LED strips tend to form a common example of indirect sources of light used in our daily life.
5. Electric Bulbs
Almost all artificial sources of light are prominent examples of indirect sources of light. This is because during propagation, a major portion of the light radiations emitted by electric bulbs, tube lights, lamps, and other manmade sources of light encounter reflection, refraction, diffusion, and scattering, thereby illuminating the surfaces or the objects indirectly.
