Between the primary and secondary rainbows, there is a dark band known as Alexandar.s dark band. This is because

Options

A. light scattered into this region interfere destructively.
B. there is no light scattered into this region.
C. light is absorbed in this region.
D. angle made at the eye by the scattered rays with respect to the incident light of the sun lies between approximately `42^@" and "50^@`.

Answer

B, D

Explanation

Alexandar.s dark band is a region between primary and secondary rainbows, the light rays scattered from which, do not enter into the eyes of an observer (aiming at rainbows) and hence such a region appears to be dark i.e. it is not seen. Thus option (B) is correct.
When we observe primary and secondary rainbows at a time, we find that primary rainbow gets finished at `42^@` whereas secondary rainbow starts at `50^@` (approximately). Hence region between these two rainbows appears to be dark which is known as Alexandar.s dark band. Thus option (D) is also correct.