The speed of light in a transparent medium is 0.6 times that of its speed in vacuum. What is the refractive index of the medium?

Explanation

To find the refractive index of a medium where the speed of light is given as a fraction of its speed in vacuum, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the relationship between speed of light in vacuum and in a medium**:
The speed of light in vacuum is denoted as \( c \), and the speed of light in the medium is denoted as \( v \). The refractive index \( n \) of the medium is defined as:
\[
n = \frac{c}{v}
...