Question

Light of wavelength $4000A^o$ is incident at small angle on a prism of apex angle$4^o$. The prism has $n_v=1.5$ and $n_r=1.4$. The angle of dispersion produced by the prism in this light is - $(n_v\to$ refractive index for violet colour)

• A. ${0.4}^o$
• B. ${0.08}^o$
• C. ${0.192}^o$
• D. None of these
  

Answer 1

The correct option is A ${0.4}^o$

Light of wavelength $\lambda =4000\mathring{A}$ is incident on a prism of apex angle A=40

also, $n_v=1.5$ $n_r=1.4$

so, dispersion produced by prism:

$D=A(n_V-n_R)$

$=4^0(1.5-1.4)={0.4}^0$ (Ans)