White light is passed through a prism of angle `4^(@)`. If the refractive indices for red and blue colours are 1.641 are 1.659 respectively, then calculate the angle of deviation between them, also calculate the dispersive power.

Explanation

Angle of deviation,
`delta=(mu_(y)-1)A=((mu_(r)+mu_(b))/2-1)4^(@)`
=`((1.641+1.659)/2-1)xx4^(@)=(1.65-1)xx4^(@)=2.6^(@)`
Dispersive power,
`omega=(mu_(b)-mu_(r))/(mu_(y)-1)=(1.659-1.641)/(1.650-1)=0.028`