[填空题]
(a) Suppose for a conventwcbsm;) vf7+ ni nt;:1f u ; b*lzvzwi,ov;ysf,onal X-ray image that the X-ray beam consists of parallel rays. What would be the magnific;fw nto v;, lvis,;z:fyz*1buation of the image? a the magnification is
(b) Suppose, instead, the X-rays come from a point source (as in Fig. Below) that is 15 $cm$ in front of a human body 25 $cm$ thick, and the film is pressed against the person’s back. Determine and discuss the range of magnifications that results. $m_1$ = the magnification is
