Is rainbow a prismatic spectrum or grating spectrum ?

[mkbh_10]

Is rainbow a prismatic spectrum or grating spectrum ?


I think it is a grating spectrum as

Deviation Order(violet least and red most) is same as that of grating
Source is at infinity (sun)
Image is at infinity

 

[NoTime]

Try this
http://en.wikipedia.org/wiki/Rainbow

 

[pam]

A rainbow is not a grating spectrum.
It is caused by refraction as the light passes in and then back out of each drop of water.