Question

if the image formed by a lens is always diminished and erect ,what type of lens it is

Answer 1

Size & orientation of image formed by a lens depends upon the position of the object & focal length of lens.

So, it is nearly impossible to make a lens which always creates perticular sized image.

Answer 2

It will be convex becoz convex mirror always forms virtual ,erect and diminished images
hope it helped!!