What is total internal reflection?
When a ray of light travelling in denser medium enters into a rarer medium, it bends away
from the normal. If the angle of incidence ‘i’ increases’ the angle of refraction ‘r’ also
increases. For a particular value of the angle of incidence, the angle of refraction becomes
90°. The angle of incidence, that cause the refracted ray in the rarer medium to bend
through 90° is called critical angle.
When does total internal reflection occur?
When the angle of incidence becomes larger than the critical angle, no refraction occurs.
The entire light is reflected back into the denser medium. This is known as total internal
reflection of light.It is shown in figure below:
What are the conditions necessary for tirf ?
Total internal reflection takes place only when:
Light should passes from denser medium to rare medium.
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The angle of incidence must be greater than critical angle.
Examples of total internal reflection
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Underwater reflection of turtle.
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Mirage is the image of some distant object that appears .
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A fish which looks like water above as mirror.
Applications of total internal Reflection
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Optical fibres
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Endoscope
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Periscope
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Binoculars
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Prisms