someone please help me with the 19th question
Answers
A:-In optics, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency. Media having this common property may be termed dispersive media. Sometimes the term chromatic dispersion is used for specificity.
Scattering refers to reflection of light. ... Bouncing (particularly of white light) doesn't split the constituent colours of the electromagnetic wave. On the other hand dispersion causes the light to split into its constituent colours. Pass a beam of white light through a prism and you will see VIBGYOR; that's dispersion.
Ray AB is incident normally as shown in fig. (a), so dispersion does not happen in the prism. But, the emergent beam gets dispersed.
In Fig. (b), dispersion occurs both inside and outside the prism as the ray is incident at an angle on the prism.
Dispersion cause the light to split in its constituent colours i.e. in seven band of colours (VIBGYOR).
Example : formation of rainbow in sky.
Scattering of light is different from dispersion of light bcoz scattering of light means the reflection of light (bouncing of white light ).
Example : sky would appear black in day time if earth had no atmosphere.
Another example , colour of clouds is blue.
For other question see the attachment.
