Invisible Man

One interesting fact that I got to know from the many quiz competitions that I have participated in so far is that invisible men are blind. The reasoning being thus. Invisibility in any medium means being one with that medium. When that happens the refractive index of the invisible body becomes same as that of the medium. In such a case, light does not converge at the retina of the eye and no image is formed. Hence invisible man cannot see. So the next time you want to get invisible, beware!!