Advertisements
Advertisements
Question
A narrow beam PQ of white light is passing through a glass prism ABC as shown in the diagram.
Trace it on your answer sheet and show the path of the emergent beam as observed on the screen DE.
(i) Write the name and cause of the phenomenon observed.
(ii) Where else in nature is this phenomenon observed?
(iii) Based on this observation, state the conclusion which can be drawn about the constituents of white light.
Solution
(i) Dispersion of light
Cause: The dispersion of white light occurs because colors of white light travel at different speeds through glass prism. Different colours undergo different deviations on passing through prism.
(ii) Rainbow is the example of dispersion of light observed in nature.
It is caused due to dispersion of sunlight by water droplets in the atmosphere. It always forms in the direction opposite to the sun.
(iii) White light is a mixture of seven colours. The sequence of colours given by the prism is Violet, Indigo, Blue, Green, Yellow, Orange and Red. VIBGYOR is the acronym for this sequence. The red light bends the least and violet light bends the most.
APPEARS IN
RELATED QUESTIONS
In the formation of spectrum of white light by a prism:
which colour is deviated least?
What happens when a ray of ordinary light is passed through a triangular glass prism?
What acts as tiny prisms in the formation of a rainbow?
Out of air and glass, which is optically rarer? Give reason.
What do you understand by the term spectrum? Name the various colours present in the spectrum of sunlight.
A student has to trace the path of a ray of light through a glass prism. List four precautions he should observe for better results.
Suggest one way, in each case, by which we can detect the presence of Infrared radiations.
The phenomena of light involved in the formation of rainbow are ______.
Assertion: We can see the rainbow in the sky when the rain starts falling after a spell of bright sunlight.
Reason: The rainbow is formed due to the dispersion of light.
