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Question
Between the primary and secondary rainbows, there is a dark band known as Alexandar’s dark band. This is because ______.
- light scattered into this region interfere destructively.
- there is no light scattered into this region.
- light is absorbed in this region.
- angle made at the eye by the scattered rays with respect to the incident light of the sun lies between approximately 42° and 50°.
Options
a and c
a and d
b and d
c and d
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Solution
a and d
Explanation:
The Alexandar’s dark band lies between the primary and secondary rainbows, formed due to light scattered into this region interfere destructively. The primary rainbows subtend an angle of nearly 41° to 42° at the observer’s eye, whereas secondary rainbows subtend an angle of nearly 51° to 54° at the observer’s eye w.r.t. incident light ray.
Hence, the scattered rays with respect to the incident light of the sun lie between approximately 42° and 50°.
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