In a certain spectrum produced by a glass prism of dispersive power `0.031`, it was found that `mu_r = 1.645 and mu_b = 1.665`. What is the refractive index for yellow colour ?

Explanation

Here, `omega = 0.031`
`mu_r = 1.645, mu_b = 1.665 , mu = ?`
As `omega = (mu_b - mu_r)/(mu - 1)`
`:. mu - 1 = (mu_b - mu_r)/(omega) = (1.665 - 1.645)/(0.031) = (0.020)/(0.031)`
=`0.645`
`:. mu = 0.645 + 1 = 1.645`.