Question

how to find out if an object is convergent or divergent

Answer 1

If depends that the object is a lens or a mirror.

If its a lens then,

                if its outer surfaces are bulged outwards then it is converging.

                if its outer surfaces are bent inwards then it is diverging.

If it is a mirror then,

                if its reflecting surface is bulged outwards then it is diverging.

                if its reflecting surface is bent inwards then it is converging.

Hope it helps.