Question

What happens when parallel rays fall on convex lens

Answer 1

When parallel rays fall on convex mirrors all the rays get diverged at all directions but all the rays appear to meet at a point,which is at the back of the mirror, called focus.
Just take look at the image.....⤴

Answer 2

any incident ray travelling parallel to the principal axis of a diverging lens will refract through the lens and travel in line with the focal point . these days will actual reach the lens before the the focal point .

I think it may help u