Total Internal Reflection

• total internal reflection is the total reflection of a beam of light at the   boundary of two mediums,when the angle of incidence in the optically denser medium exceeds a specific critical angle.
• the boundary between the two mediums acts like a perfect plane mirror where total internal reflection occurs.
• the critical angle is the angle of incidence in the optically denser medium for which the angle of reflection in the less dense medium is 90'.
• the conditions required for the occurence of total internal reflection are:

1. the light ray must travel from an optically denser medium to a less dense medium.
2. the angle of incidence must be greater than the critical angle,that is i>c

• example:it will occur when passing from glass to air.

Application-application of total Internal Reflection 

• optical fibres -> used in endoscopes and telecommunications.
• rain sensors -> to control automatic windscreen.
• prismatic binoculars -> to get a very clear image.
• gonioscopy -> to view the anatomical angle formed between the eye's cornea   and iris.
• fingerprinting devices -> to record an image of a person's fingerprint without the use of ink.