Question

Study the figure in which the path of a ray of light going from Medium 1 to Medium 2 is shown.

1. Out of the two Media - Medium 1 and Medium 2, in which is the speed of light more?
2. State reason of bending of the refracted ray away from the normal.
3. Express refractive index of Medium 2 with respect to Medium 1 in terms of speed of light in two media.

Answer 1

(a) The speed of light is more in Medium 2.

Explanation: The refracted ray bends away from the normal, indicating Medium 2 is optically rarer than Medium 1. Rarer mediums carry light faster than denser ones.

(b) The refracted ray bends away from the normal because light is traveling from a denser medium (Medium 1) to a rarer medium (Medium 2). According to Snell’s Law, when light passes from a medium of higher refractive index to a lower refractive index, its speed increases, and as a result, the ray bends away from the normal.

(c) The refractive index of Medium 2 with respect to Medium 1 is given by:
`n_21 = (v_1)/(v_2)`
where:

n₂₁ = refractive index of Medium 2 with respect to Medium 1.

v₁ = speed of light in Medium 1.

v₂ = speed of light in Medium 2.

Since the speed of light in Medium 2 is greater than in Medium 1 (v₂ > v₁), we conclude that n₂₁ < 1, meaning Medium 2 is optically rarer than Medium 1.