Assertion : The rainbow is seen sometimes in the sky when it is raining. When one sees a rainbow, one’s back is towards the sun.

Reason : Internal reflection from water droplet causes dispersion. The final ray is in the backward direction

The rainbow is seen during or after raining as there are lot of water droplets suspended in the air at that time. As the rainbow is caused by the total internal reflection of the sunlight from the droplets, the final ray is in the backward direction and so one always sees a rainbow in a direction opposite to the sun.