The optical phenomenon that is primarily responsible for the observation of rainbow on a rainy day is

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Q: 31 (CDS-I/2017)
The optical phenomenon that is primarily responsible for the observation of rainbow on a rainy day is

question_subject: 

Science

question_exam: 

CDS-I

stats: 

0,81,77,28,17,95,18

keywords: 

{'optical phenomenon': [0, 0, 0, 1], 'rainbow': [0, 0, 0, 3], 'diffraction': [0, 2, 2, 9], 'dispersion': [0, 0, 1, 16], 'reflection': [1, 1, 2, 19], 'rainy day': [0, 0, 0, 1], 'interference': [0, 2, 1, 5], 'observation': [0, 0, 0, 5]}

The correct answer is option 3 - dispersion.

Dispersion is the optical phenomenon that is primarily responsible for the observation of a rainbow on a rainy day. When sunlight passes through raindrops in the atmosphere, the light is refracted or bent and then dispersed into its constituent colors. This dispersion occurs because different colors of light have different wavelengths and travel at slightly different speeds through the raindrops.

As the light enters the raindrop, it is refracted, or bent, and then reflects off the inside surface of the drop. This causes the light to separate into different colors. The different colors of light are then refracted again as they exit the raindrop and are dispersed further.

Therefore, when many raindrops in the atmosphere refract and disperse sunlight, we observe a rainbow. The rainbow appears as a circular arc of colors, with red on the outer edge and violet on the inner edge. This is because light of different colors is refracted at slightly different angles within the raindrops, resulting in the separation and arrangement of colors that we see as a rainbow.