Refraction of rainbow seen in prism but not in glass slab because sides of prism is inclined to each other at equal angle and and so dispersion only occur in prism but the glass slab give lateral displacement that\’s why the reflection of refraction of rainbow seen in prism but not in glass slab
The glass slab produces dispersion but the resulting rainbow like spectrum cannot be seen. This is due to the fact that all refracted wavelength emerges parallel to their incident direction
A glass slab produces dispersion but the resulting rainbow like spectrum effect cannot be seen. This is due to the fact that all the refracted wavelengths emerge parallel to their incident direction. Thus the emergent beam is a parallel beam in case of a glass slab, while it is divergent in case of a prism.