Splitting of light into its constituents colours is known as
Dispersion
Reflection
Refraction
Diffraction.
Dispersion
Explanation for correct option:
A: Dispersion
Dispersion is defined as the phenomenon of splitting visible white light into its components.
Explanation for incorrect option(s):
B: Reflection
When a ray of light fall on an object, light from that object bounces back those rays of light to our eyes, and this is known as reflection.
C: Refraction
Refraction is defined as the change in direction of the light waves when passing from one medium to another medium.
D: Diffraction
Diffraction of light is defined as the bending of light around corners such that it spreads out and illuminates the area where a shadow is expected.
Hence, option A is correct