Question

9) State the laws of refraction of light. Explain the term 'absolute refractive index
of a medium' and write an expression to relate it with the speed of light in vaccum
of focal​

Answer 1

Explanation:

Laws of refraction state that: The incident ray, reflected ray and the normal, to the interface of any two given mediums; all lie in the same plane. The ratio of the sine of the angle of incidence and sine of the angle of refraction is constant.

Absolute refractive index is the refractive index of a medium in vacuum. More specifically, it is the ratio of the spped of light in vacuum to the speed of light in that medium. It is always greater than one 

U=C/V

Answer 2

Answer:

• Refractive index is defined as the ratio of the speed of light in a vacuum to its speed in a specific medium.
• When a beam of light passes through two different media via an interface, its behaviour is governed by the laws of refraction of light.
• These laws are also known as Snell’s law.
• The two laws followed by a beam of light traversing through two media are:
• 1) The ray of light incident to the interface, the normal trajectory of the beam (from the point of incidence), and the refracted ray must all lie in the same plane
• .n = c/ν
• where
• n = Refractive index
• .c = Velocity of light in a vacuum ( 3 × 10^8 m/s).
• v = Velocity of light in a substance.
• 2) For any two different media, the since of the angle at which the beam of light is incident is always proportional to the sine of the angle at which the refracted ray emerges. In other words, the quotient of the sine of the angle of incidence and the sine of the angle of refraction is always constant.

• n=sini.sinr.