According to newton's corpuscilar theory of light, when corpuscles of light strike the interface `XY`, Fig. separating a denser medium from a rarer medium, the component of their velocity along `XY` remains the same :
If `v_(1)` is velocity of light in rarer medium (air) `v_(2)` is velocity of light in denser medium (water) `i` is angle of incidence, `r` is angle of reflection, then
component of `v_(1)` along `XY = v_(1) sin i`
cpmponent of `v_(2)` along `XY = v_(2) sin r`
As `v_(1) sin i = v_(2) sin r :. (v_(2))/(v_(1)) = (sin i)/(sin r) = mu`
As `mu gt 1 :. v_(2) gt v_(1)`
i.e. light should travel fater in water than in air.This prediction of Newton's theory is opposite to the experiment result.
Huygens wave theory predicts that `v_(2) lt v_(2)`, which is consists with experiment.
