Dispersion of light


 
 
Concept Explanation
 

Dispersion of Light

We see colours all around us. The blue sky, green leaves, red roses, yellow sunflowers, colourful birds and butterflies, etc., are just some of the colours we see in nature. And then we have the colours of our clothes, pens, pencils, houses, vehicles, and so on. The colours we see depend on the colour of light entering our eyes from an object or a source of light. Different sources of light may produce lights of different colours. A sodium-vapour lamp, for example, produces a yellowish light. The flame of a gas stove emits blue light. But sunlight does not appear to have a colour. The same is true of certain types of bulbs we use at home. We call such light (i.e., those that appear colourless) white light.

Though white light does not appear coloured, it is actually a mixture of lights of different colours present in a definite proportion. Lights of different colours have different wavelengths. So, they behave differently. For example, they travel at different speeds. This makes the refractive index of a transparent material slightly different for different colours of lights. So, lights of different colours bend by different amounts on refraction. Therefore, under certain conditions, when white light gets refracted, its components bend by different amounts and separate out. You must have seen this happen when sunlight passes through a glass of waterfalls on the table or the floor, producing a band of colours. The phenomenon of splitting light into its component colours due to the dependence of refractive index on wavelength is called the dispersion of light.

Activity Showing dispersion of light:

Step 1: Take a plane mirror of suitable size.

Step 2: Place it in a bowl (Katori). Fill the bowl with water.

Step 3: Put this arrangement near a window such that direct sunlight falls on the mirror.

Step 4: Adjust the position of the bowl such that the reflected light from the mirror falls on a wall. If the wall is not white, fix a sheet of white paper on it.

.... (More Text Available, Login?)
Sample Questions
(More Questions for each concept available in Login)
Question : 1

Lights of______________ colors have___________ wavelengths .

Right Option : A
View Explanation
Explanation
Question : 2

Which color of light has the minimum wavelength?

Right Option : A
View Explanation
Explanation
Question : 3

Different sources of light may produce lights of_________  colors.

Right Option : B
View Explanation
Explanation
 
 
 


Students / Parents Reviews [20]