The wavelength of a light ray in vacuum is 5896 Å . What will be its velocity and wavelength when it passes through glass ? Given refractive index of glass =1.5 and dvelocity of light in vacuum = ` 3 xx 10^(8) m s^(-1)` .

Explanation

Here, `lambda` = 5896 Å , c `3 xx 10^(8)` m.`s^(-1) mu_(g)` =1.5
we know `mu _(g) = ( c )/c_(g)`
or `c_(g)=(c)/(mu_(g))=(3xx10^(8))/(1.5)=2 xx 10^(8) "m"" " s^(-1)`
Again n `lambda ` =c (in vacuum ) , n`lambda_(g)= c_(g)` (in glass )
`:." " (nlambda_(g))/(nlambda )=(c_(g))/(c)`
or `lambda_(g)=lambda(""^(c)g)/(c)=(lambda)/(mu_(g))=(5896)/(1.5)=3931` Å