Question

THE SPEED OF LIGHT IN VACCUM IS 3X10^8 m/s AND THE REFRACTIVE INDEX OF And MEDIUM WITH RESPECT TO VACCUM IS 1.4.FIND THE SPEED OF LIGHT IN THAT MEDIUM

Answer 1

Answer:

The absolute refractive index of a medium is 2.14.

Step-by-step explanation:

The speed of light in vaccum,  

The speed of light in a medium,  

Let n is the absolute refractive index of a medium. It is given by the ratio of speed of light in vaccum to the speed of light in a medium. So,

So, the absolute refractive index of a medium is 2.14.

Answer 2

Step-by-step explanation:

Speed of light in vacuum (c) = 3 × 10⁸ m/s

Refractive index (μ) of the medium = 1.4

Speed of light in the medium(v) = ?

Using formula,

${\sf{\bf{Refractive \: index(μ) = \dfrac{Speed \: of \: light \: in \: Vacuum(c)}{Speed \: of \: light \: in \: the \: medium(v)}}}} \\ \\ \\\rm:\implies{v= \frac{c}{μ}} \\ \\ \\\rm:\implies{v= \frac{3×10⁸ \: m/s}{1.4}} \\ \\ \\\bf\therefore{v =2.14 \times 1 {0}^{8}m/s.}$

Hence, speed of light in that medium is 2.14 × 10⁸ m/s.

Additional Information

Laws of Refraction

• The first law states that the incident ray, the normal to the point of incidence and the refracted ray all lie in the same plane.

• The second law is based on the pair of media through which the light undergoes refraction. It states that the ratio of sine of angle of incidence to the sine of angle of refraction is always constant and is known as the refractive index of the second medium with respect to the first.

$\rm\dfrac{sin\:i}{sin\:r}=constant (μ)$

This law was given by Willebrord Snell and hence it is popularly known as the Snell's law.

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Refractive Indices of Some Media with Respect to Vacuum

$\begin{gathered}\begin{array}{|c|c|}\space \rm\underline{Medium}&\rm\underline{Refractive}\space\sf\underline{Index}\\{\sf{Air}}&1.0003\\{\sf{Water}}&1.33\\{\sf{Alcohol}}&1.36\\{\sf{Glass}}&1.5\\ \sf{Diamond}&2.42\end{array}\end{gathered}$

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