Physics · JEE | Ray Optics and Optical Instruments

For three media, if \( n_{32} \) is the refractive index of medium 3 with respect to medium 2 and \( n_{31} \) is that of medium 3 with respect to medium 1, then \( n_{32} \) can be expressed as:

1. A
   \( n_{32} = \frac{n_{31}}{n_{12}} \)
2. B
   \( n_{32} = n_{31} + n_{12} \)
3. C
   \( n_{32} = n_{31} \times n_{12} \)
4. D
   \( n_{32} = \frac{n_{12}}{n_{31}} \)