An artist may say 'black is a colour'. But physicist says, 'black is just a absence of light. A green leaf absorbs all the colours in the sunlight except green. When it reflect only green light, it looks green. A black shirt will absorb all the light and emits none. Hence it looks'black'. Consequently the wearer will feel warm.
Flowers normally have soft petals. Hence they have short life. Had there been a black flower, it would absorb all the solar radiation and whither quickly. The flowers normally have white or bright colours.
Solar panels, umbrella, solar cooker are black so that they can absorb the sun's heat fully.
There is star with infinite density, heavy mass and enormous gravity. It attracts and absorbs everything due to its immense gravity. Even it swallows light. Hence it is called 'black hole'.
Take black iron metal. Heat it. First it will turn yellow, then orange, red, blue, and white. So a black body is good emitter also. The 'black body' helped to discover 'photons' and gave birth to 'quantum physics'.
Ultraviolet light is called black light since it is invisible. Black light can be used to detect counterfeit bank notes. Some features in the 'bank notes' are visible only under UV light.
When two light waves meet, we think it will result in more brightness. But sometimes, the two light wave cancel each other and gives us darkness. (can be shown only in a lab).
There is also bright side to darkness. Without darkness, we can not explore sky and cosmos; we cannot sleep peacefully; we cannot enjoy a movie; we cannot study and under stand the light; we cannot take a photo-camera means dark room; we cannot enjoy laser show and so on.
All the electronic gadgets are black in colour. Other colours and white will disturb the picture that is displayed.
Black hair bordering a girl's face adds more beauty.
Without dark, brightness is a boredom.
-------------------------------------------------------------------------------------------------
Comments
Post a Comment