Physics

(a) A boy uses blue colour of light to find the refractive index of glass, then he repeats the experiment using red colour of light. Will the refractive index be the same or different in the two cases? Give a reason to support your answer.
(b) A ray of light incident on a glass slab and follow the path as shown below. If a mirror is placed at S, such that emergent ray falls normally on it, then
I. Draw diagram to show the path of ray reflected from the mirror.
II. On the basis of which principle this refraction of ray is done?
$A ray of light incident on a glass slab and follow the path as shown below. If a mirror is placed at S, such that emergent ray falls normally on it, then I. Draw diagram to show the path of ray reflected from the mirror. II. On the basis of which principle this refraction of ray is done? Physics Sample Paper Solved ICSE Class 10.$

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(a) The speed of blue light in glass is less that of red light.

i.e. c_b < c_r

We know that,

$μ = \dfrac{\text{Speed of light in vacuum or air (c) }}{\text {Speed of light in glass (V)}} \\[0.5em]$

Hence, the refractive index of blue light is greater than that of red light.

i.e. μ_b > μ_r.

Hence, the refractive index of red and blue light in glass will be different.

I. Below diagram shows the path of the ray reflected from the mirror:

II. Refraction of ray is done on the basis of principle of reversibility of light.

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