During the rainy season you might have observed a bow shaped multicoloured strip in the sky. This is called rainbow. This strip has seven colours-red at the top and violet at the bottom. Other colours lie in between these two. How is the rainbow formed?
The sunlight which appears to be white is actually composed of seven colours. These seven colours are-Violet, indigo, blue, green, yellow, orange and red. The wavelength-wise distribution of these colours is called spectrum. After the rains, the atmosphere is full of small water-drops. When the white light coming from the sun enters these drops, its seven colours are separated. These rain-drops work like prisms. As the prism separates the seven colours of white light, these drops also sweparate the different colours. The separation of seven colours of the sunlight is called dispersion. These colours after being totally reflected from the back side of the rain drops come out as separate colours. When the rays of these colours reach our eyes, they give us the appearance of the rainbow. The rainbow is circular because the sun is also circular. Sometimes a second rainbow can also be seen. This is called secondary rainbow. This is fainter in comparison to the first one and the sequence of its colours is reversed i.e. violet colour occupies the upper most position while the red is the lower most. This rainbow is formed due to those rays which have been reflected twice inside the water drops. The rainbow is generally seen only when the sun is at our back and the cluster of water drops are in front of our eyes, i.e. when we stand in between the sun and the cluster of water drops. It is essential for the formation of the rainbow that the sun is shining after the rain. It is also essential that the sun, our eyes and the centre of the rainbow lie on the same straight line. To remember the order of colours in the spectrum, we should remember the word VIBGYOR. Each letter of this word represents one colour i.e. V for violet, I for indigo, B for blue, G for green, Y for yellow, O for orange and R for red.
The sunlight which appears to be white is actually composed of seven colours. These seven colours are-Violet, indigo, blue, green, yellow, orange and red. The wavelength-wise distribution of these colours is called spectrum. After the rains, the atmosphere is full of small water-drops. When the white light coming from the sun enters these drops, its seven colours are separated. These rain-drops work like prisms. As the prism separates the seven colours of white light, these drops also sweparate the different colours. The separation of seven colours of the sunlight is called dispersion. These colours after being totally reflected from the back side of the rain drops come out as separate colours. When the rays of these colours reach our eyes, they give us the appearance of the rainbow. The rainbow is circular because the sun is also circular. Sometimes a second rainbow can also be seen. This is called secondary rainbow. This is fainter in comparison to the first one and the sequence of its colours is reversed i.e. violet colour occupies the upper most position while the red is the lower most. This rainbow is formed due to those rays which have been reflected twice inside the water drops. The rainbow is generally seen only when the sun is at our back and the cluster of water drops are in front of our eyes, i.e. when we stand in between the sun and the cluster of water drops. It is essential for the formation of the rainbow that the sun is shining after the rain. It is also essential that the sun, our eyes and the centre of the rainbow lie on the same straight line. To remember the order of colours in the spectrum, we should remember the word VIBGYOR. Each letter of this word represents one colour i.e. V for violet, I for indigo, B for blue, G for green, Y for yellow, O for orange and R for red.
0 comments:
Post a Comment