The observation made by Swarali while doing the experiment are given below. Based on these write answers to the questions :
Swarali found that the light ray travelling from the denser medium to rarer medium goes away from the normal. If the angle of incidence (i) is raised by Swarali, the angle of refraction (r) went on increasing. However after certain value of the angle of incidence the light ray is seen to return back into the denser medium.
1) What is the specific value of∠i called?
2) What is the process of reflection of incident ray into denser medium called?
3)Draw the diagrams of three observations made by Swarali.
1) The specific value of ∠ i called critical angle.
2) Total internal reflection.
Observation 1 : When i1< iC , then refraction takes place and refracted ray moves away from
normal. r1 > i1
Observation 2 : when i1 =iC then refracted ray becomes perpendicular to normal.
Observation 3 : When i3 > iC then total internal reflection takes place.