Refractive index of an optical medium changes with 1. the nature of the medium. 2. the change in the angle of incidence of the ray 3. colour of the incident ray. Select the correct answer using the code given below :

The refractive index (n) of an optical medium is defined as the ratio of the speed of light in a vacuum to its speed in that medium [c3, t2]. It is a characteristic property that depends on the nature of the medium, as different materials (like water, glass, or diamond) slow down light to different extents [c2, t1]. Additionally, the refractive index varies with the frequency or wavelength (colour) of the incident light, a phenomenon known as dispersion [t3, t8]. For instance, blue light typically experiences a higher refractive index than red light in the same medium [t3]. However, the refractive index is an intrinsic property of the medium for a specific wavelength and does not change with the angle of incidence [c1, t1]. While the angle of refraction changes as the angle of incidence varies (Snell's Law), the ratio (n) remains constant for a given pair of media and colour [c1, t7].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > Activity 9.10 > p. 148
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > 9.3.2 The Refractive Index > p. 149
3. [3] Science , class X (NCERT 2025 ed.) > Chapter 9: Light – Reflection and Refraction > What you have learnt > p. 159
4. [4] https://www.ncbi.nlm.nih.gov/books/NBK594230/
5. [5] https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/refraction-index
6. [6] https://www.britannica.com/science/refractive-index