Answer:
Refractive index, n = 2.419
Step-by-step explanation:
It is given that,
Speed of light in the medium,
![v=1.239* 10^8\ m/s](https://img.qammunity.org/2020/formulas/physics/college/uv9l6jw110km7ih4ds7dkx4v2z73xx1ei6.png)
Speed of light in the vacuum,
![c=2.998* 10^8\ m/s](https://img.qammunity.org/2020/formulas/physics/college/cepbcvjbbnmd7icf6aa0n1cc1b0zjjwdn3.png)
Let n is the index of refraction for a medium. We know that the refractive index for any medium is equal to the ratio of speed of light in vacuum to the speed of light in medium. It can be written as :
![n=(c)/(v)](https://img.qammunity.org/2020/formulas/physics/college/8vxgo8hgsplc2mt5905rxjhpto1i1wo6f1.png)
![n=(2.998* 10^8\ m/s)/(1.239* 10^8\ m/s)](https://img.qammunity.org/2020/formulas/physics/college/ei7vd2aqr79oj39jbg35dj6sb6xg4ytl4b.png)
n = 2.419
So, the index of refraction for a medium is 2.419. Hence, this is the required solution.