Question

guess and write why the rainbow appears semicircular on sky

Answer 1

Because that is the location of rain drops that are at correct angle between the sun and our eyes A rainbow is actually in circle shape but normally the ground stops the rain drops so there are none on the bottom part of the circle. Pilots can see the full circle rainbow if they look down at clouds or rain

Answer 2

In actual rainbow is in form of a circle not a semicircular .It appears semicircular due to the earth stops the raindrops and rainbow is a prism formed due to rain drops when the sunlight passes through it. Hence it appears that the rainbow is semicircular in shape .The pilots can see full rainbow most of the time