In such a case medium 2 is said to be optically denser (or
denser, in short) than medium 1 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