Chapter 14, Problem 3TE

Solution

To determine: The reason for a secondary rainbow is dimmer than a primary bow.

Answer:

A secondary rainbow is dimmer than a primary bow due to an extra reflection of light rays in the formation of the secondary bow.

Explanation:

When light is dispersed and reflected by water droplets, a rainbow is formed. A rainbow consists of a primary and secondary bow.

A secondary rainbow is observed just above the primary rainbow on rainy days. A primary rainbow is formed when a water droplet refracts the sunlight twice and reflects it for a single time. The secondary rainbow is produced when the refraction and reflection of light take place twice.

Thus, the formation of a secondary rainbow is caused by one extra reflection than that in primary rainbow formation. Due to this extra reflection, the secondary rainbow appears dimmer than the primary.

Conclusion:

Therefore, a secondary rainbow is dimmer than a primary bow due to an extra reflection of light rays in the formation of the secondary bow.