Physics Olympiad USA Math Olympiad

Light through Prisms (KVPY ’10)

White light is split into a spectrum by a prism and it is seen on a screen. If we put another identical inverted prism behind in contact, what will be seen on the screen?

(A) Violet will appear where red was

(B) The spectrum will remain the same

(C) There will be no spectrum but only the original light with no deviation

(D) There will be no spectrum, but the original will be laterally displaced


The system will behave as a slab since an inverted prism is put behind in contact with the first prism. Hence, there will be no spectrum, but only original light with no deviation.