1) A simple magnifier allows us to put the object closer to the eye than we could normally focus and forms an enlarged virtual images.
2) The principle behind this is angular magnification.
3) The magnification is Ma = 25/f y for the close focus point, but since that causes
eye strain, it is usually desirable to put the images at infinity giving Ma = 25/f.
4) So, he ful the size of object increased. The reason is about mentioned.
5) Angular magnification : The ratio of the angle subtended at the eye by the image formed by an optical instrument to the angle substended at the eye by the object being viewed.