تسجيل الدخول

تسجيل

Relative Size of Object and Image

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-454

2025-12-25

723

To get an expression for the relation between the size of the object and that of its image, it is only necessary to study the geometrical construction of such a figure as that in case (b). From similar triangles in Fig. 1 it is seen that

AB: A'B' = CD: CD'.

That is, the length of the object is to the length of the image as the distance of the object from C is to the distance of the image from C. Experiment shows that

in which F is the principal focal length, or practically half the radius of curvature, D, the distance of the object from the mirror, and D, the distance of its image. From this formula any one of these three distances can be found if the other two are known.