A passenger in an aeroplane shall

Options

A. never see a rainbow
B. may see a primary and a secondary rainbow is concentric arcs.
C. may see a primary and a secondary rainbow as concentric arcs.
D. shall never see a secondary rainbow.

Answer

To solve the question about what a passenger in an aeroplane can see regarding rainbows, we will analyze the phenomenon of rainbows and how they appear from different perspectives.

### Step-by-Step Solution:

1. **Understanding Rainbows**:
- Rainbows are optical phenomena that occur due to the refraction, dispersion, and reflection of light in water droplets. There are two main types of rainbows: primary and secondary.
- The primary rainbow is formed by one internal reflection within the droplet, while the secondary rainbow is formed by two internal reflections.

2. **Observation from the Ground**:
- When standing on the ground, a person typically sees only the primary rainbow. This is because the primary rainbow is brighter and more intense than the secondary rainbow, which is fainter and appears outside the primary arc.

3. **Observation from an Aeroplane**:
- A passenger in an aeroplane has a different perspective. From this height, they can see the entire circular arc of the rainbow rather than just a segment.
- This is because the passenger is above the water droplets that create the rainbow, allowing them to see both the primary and secondary rainbows.

4. **Formation of Concentric Circles**:
- The light from the sun enters the water droplets and undergoes total internal reflection. The passenger can see multiple reflections from different droplets, resulting in concentric circles of both the primary and secondary rainbows.
- Since there is no ground obstructing the view, the passenger can see the complete circular arcs of both rainbows.

5. **Conclusion**:
- Therefore, a passenger in an aeroplane will see both the primary and secondary rainbows as concentric arcs in the sky.

### Final Answer:
A passenger in an aeroplane shall see both the primary and secondary rainbow as concentric arcs.