Compute each of following question given below:
Question: A convex lens has a focal length of 0.28m.
Part I: Where on the lens axis should an object be placed in order to get a real, magnified image with a magnification of 2.0?
Part II: Where on the lens axis should an object be placed in order to get a virtual, magnified image with a magnification of 2.0?
Please explain each step and equations used.