Total internal reflection of light is possible when light enters from ____?

Total internal reflection of light is possible when light enters from ____?

جب روشنی ____ سے داخل ہوتی ہے تو روشنی کا مکمل اندرونی انعکاس ممکن ہے؟
Explanation

Total internal reflection occurs when light travels from a denser medium (like water) to a rarer medium (like air) and the angle of incidence is greater than the critical angle.