Answer the following questions:
In viewing through a magnifying glass, one usually positions one's eyes very close to the lens. Does angular magnification change if the eye is moved back?

The angular magnification decreases in a slight manner when we move our eyes back because, then the angle subtended at the eye by the image will be faintly less than the angle subtended by the image at the lens. Also, angle subtended by the object at the eye is also less than the angle subtended by the object at the lens. However, this decrease is very minute as compared to the case of image. 

Also, when the eye is separated from the lens, the angles subtended at the eye by the object and its image are not equal.
Further it may be noted that if the image is away at a very large distance and, we move our eyes back from the lens, then, the effect on magnification is negligible.