Question

You are given four sources of light each one providing a light of a single colour- red, blue, green and yellow. Suppose the angle of refraction for a beam of yellow light corresponding to a particular angle of incidence at the interface of two media is ${90}^o$. Which of the following statements is correct if the source of yellow light is replaced with that of other lights without changing the angle of incidence?

• A. The beam of red light would undergo total internal reflection.
• B. The beam of red light would bend towards normal while it gets refracted through the second medium.
• C. The beam of blue light would undergo total internal reflection.
• D. The beam of green light would bend away from the normal as it gets refracted through the second medium.

Answer 1

The correct option is C The beam of blue light would undergo total internal reflection.

For yellow light, $\gamma ={80}^{\circ }$ when $i=c$

When is is kept same, $c$ must be smaller for total internal reflection,

$u=\frac{1}{\sin c}=>\sin c=\frac{1}{\mu }$

velocity of light $=f\lambda$ when frequency of Wave unchanged with medium

$\begin{array}{c}v\propto \lambda \\ v\propto \frac{1}{\mu }\end{array}$

Alc to VIBCoyoR, amang all the given source of light blue light has smallest waveleng $H_1$ as

So${\lambda }_{\text{blue}}<{\lambda }_{\text{yellow}}$

it means${\lambda }_{\text{blue}}<{\lambda }_{\text{yellow}}$

So that critical angle for blue is tess than yellow $(\sin c{)}_{\text{blue}}<(\sin C)$

$\left(\sin c\alpha \frac{1}{\mu }\right)$

The beam of blue light would undergo total internal reflection.

Hence, $\left(c\right)$ is correct ophon,