which best explains why rainbows only appear when there is rain ans sun
Rainbows only appear when there is rain and sun because they are created through the interaction of sunlight with raindrops.
When sunlight enters a raindrop, it undergoes a process called refraction, where the light ray bends as it passes from one medium (air) to another (water). This bending of light causes the different colors of light to separate and spread out within the raindrop.
After undergoing refraction inside the raindrop, the separated colors bounce off the inner surface of the raindrop, which results in another bending of the light rays. This additional bending is called internal reflection.
Once the light rays have undergone both refraction and internal reflection inside the raindrop, they exit the raindrop and disperse into the surrounding air. This dispersion then forms a circular arc of colored light, which we perceive as a rainbow.
For us to see a rainbow, the sunlight must pass through raindrops in the air, while our viewpoint is opposite the direction of the sun. This means that the sun must be low in the sky, such as early in the morning or late in the afternoon when rain showers are more common.
Therefore, rainbows only appear when there is both rain and sun because it is the specific combination of raindrops acting as prisms and sunlight that allows us to see the beautiful spectrum of colors in the sky.