Question

Convex lens is a converging lens which converges light rays from infinity..

Why does our eye dont burn when sunlight enters our eye ( Considering sun light is very hot and are coming from infinity)?

Answer 1

All the light rays coming from infinity are parallel to each other and hence as they are not converging they do not affect our eyes but when we use convex lens we change the direction of the rays hence it all converges into our eyes and it may damage our eyes.
You are saying that son is very hot but then its harmful rays which are UV rays cross through the ozone layer they are not able to do it and hence only the non harmful rays reached in our eyes but by using convex lens it also damages.