Prisms-- refraction and dispersion

Refraction in glass prism  - Angle of incidence and angle of emergence aren't equal as both rays aren't parallel as both rectangular surfaces aren't parallel in a prism  - Angle of incidence (1) is formed between normal against first surface and angle of incidence, angle of refraction (1) is formed between normal and angle of refraction. Angle of incidence (2) is formed between normal of second surface against said refracted ray. Angle of refraction (2) is nothing but Angle of Emergence.  -Angle of Deviation is formed between the unrefracted path of incident ray (stretched to form in diagram) and the emergent ray.

Dispersion of Light  -Dispersion of light is the phenomena in which white light, upon passing through a prism, splits itself into its constituent colours (VIBGYOR). -VIBGYOR makes up the visible spectrum, which is why when all these colours come together, white light is formed. - Every colour has a different refractive index, which is inversely proportional to its velocity, which is why violet light bends the most and is formed right at the bottom.  -Every colour also has a wavelength, which is directly proportional to its velocity, and hence red bends the least and is formed at the top and even when a rainbow is formed, red is the most prominent colour -Wavelength decreases as we go from red to orange to yellow and then eventually to indigo and violet. Similarly, Refractive Index decreases from violet, indigo, blue, green to reach its lowest value in red.  -WAVELENGTH IS DIRECTLY PROPORTIONAL TO VELOCITY AND REFRACTIVE INDEX IS INVERSELY PROPORTIONAL TO VELOCITY.  -During rain, every raindrop acts as a prism and so when the white light of the sun passes through it, and when this happens on a mass scale, a rainbow is formed.