On the other hand, if n 21 <1, r > i, the
Rationalised 2023-24
Ray Optics and
Optical Instruments
229
refracted ray bends away from the normal This
is the case when incident ray in a denser
medium refracts into a rarer medium Note: Optical density should not be
confused with mass density, which is mass
per unit volume It is possible that mass
density of an optically denser medium may
be less than that of an optically rarer
medium (optical density is the ratio of the
speed of light in two media)