Question

A ray of light travels from a medium of refractive index $$ \mu $$ to air . Its angle of incidence in the medium is $$ \theta $$ , measured from the normal to the boundary and its angle of deviation is $$ \delta $$ with the angle of refraction $$ \phi $$. A graph is plotted between $$ \delta $$ and $$ \theta $$ which is shown in the figure. Choose the correct relation from the following

Answer 1

Correct option is B. $$ \dfrac{\delta_2}{\delta_1} = 2 $$
Given: refractive index of medium u,

angle of incidence ,θ.

angle of deviation, $$\delta$$

angle of refraction,ϕ .
For θ < c, $$\delta$$ = ϕ - θ with sinϕ / sinθ = μ or ϕ = sin-1 (μsin θ).

∴ $$\delta$$ = sin-1 (μsin θ) - θ This is a nonlinear relation.

The maximum value of $$\delta$$ is $$\delta$$1 = π/2 - c for θ = c and ϕ = π/2.

For θ > c, $$\delta$$ = π - 2θ $$\delta$$ decreases linearly with θ.

$$\delta$$max = π - 2c = $$\delta$$2 = 2$$\delta$$1.

therefore, $$\delta$$2$$\div$$$$\delta$$1=2.