Does the apparent depth of a tank of water change, normally.

60 A ray of light while traveling from a denser to a rarer medium, is incident at critical angle on the interface. What is the angle of refraction in the rarer medium? 61 A glass slab is placed over a page in which letters are printed in different colours. Will the image of all the letters lie in the same plane? 63 For which colour of white light is the refractive index of a transparent medium is maximum and minimum. 64 What is total reflecting prism?