Explain total internal reflection, with the help of a neat diagram.
Explain total internal reflection, with the help of a neat diagram.
Total internal reflection––––––––––––––––––––––––––
When a light ray travels from a denser to a rarer medium, it bends away from the normal. The angle of refraction is greater than the angle of incidence.
As the angle of incidence increases, the angle of refraction also increases. For a particular angle of incidence, the angle of refraction becomes (as in diagram b) 90∘ and the refracted ray grazes the surface separating the two media. This angle of incidence is called the ‘critical angle’ and is defined for a pair of media. If the angle of incidence is increased beyond this critical angle, the ray is not refracted but gets reflected as shown in diagram (c). Then, the entire incident light is reflected back into the denser medium. This phenomenon is called the total internal reflection.
Total internal reflection––––––––––––––––––––––––––
When a light ray travels from a denser to a rarer medium, it bends away from the normal. The angle of refraction is greater than the angle of incidence.
As the angle of incidence increases, the angle of refraction also increases. For a particular angle of incidence, the angle of refraction becomes (as in diagram b) 90∘ and the refracted ray grazes the surface separating the two media. This angle of incidence is called the ‘critical angle’ and is defined for a pair of media. If the angle of incidence is increased beyond this critical angle, the ray is not refracted but gets reflected as shown in diagram (c). Then, the entire incident light is reflected back into the denser medium. This phenomenon is called the total internal reflection.
