Varying the refractive index in Snell’s Law directly affects how much the light ray bends when it passes from one medium to another.
- Greater difference in refractive indices:
When there is a large difference between the refractive indices of two media, the bending of light is more noticeable. For example, light bends more sharply when entering water from air than when entering glass from water. - Higher refractive index of the second medium:
If the second medium has a higher refractive index, the light slows down and bends toward the normal (the imaginary line perpendicular to the surface). - Lower refractive index of the second medium:
If the second medium has a lower refractive index, the light speeds up and bends away from the normal. - Critical angle and total internal reflection:
A greater difference between refractive indices results in a smaller critical angle, which means total internal reflection can occur more easily when light moves from the denser to the rarer medium.
In essence, changing the refractive index changes how much light bends, whether it bends toward or away from the normal, and whether phenomena like total internal reflection can occur.