The refractive index of flint glass for red and blue colours are 1.664 1.644 . What will be the dispersive power?

Question

The refractive index of flint glass for red and blue colours are 1.664 1.644 . What will be the dispersive power? (A) 0.305 (B) 0.0305 (C) 0.635 (D) 0.0635

Tardigrade Admin · Accepted Answer

As we know ω=(μb-μr/μ-1)[μ= mean refractive index ] μ=(μ b +μ r /2) =(1.664+1.644/2)=1.654 ω=(μ b -μ r /μ-1) ω=(1.664-1.644/1.654-1) =0.0305

Q. The refractive index of flint glass for red and blue colours are $1.664&1.644.$ What will be the dispersive power?

0.305

0.0305

0.635

0.0635

As we know
$ω = \frac{μ _{b} - μ _{r}}{μ - 1} [μ =$ mean refractive index $]$
$μ = \frac{μ _{b} + μ _{r}}{2}$
$= \frac{1.664 + 1.644}{2} = 1.654$
$ω = \frac{μ _{b} - μ _{r}}{μ - 1}$
$ω = \frac{1.664 - 1.644}{1.654 - 1}$
$= 0.0305$

Q. The refractive index of flint glass for red and blue colours are 1.664&1.644. What will be the dispersive power?