96 



ELECTROMAGNETIC RADIATIONS AND MATTER 



Figure 4-10b(i). Absorption of X Rays by Tissues. Abdomen with Barium Sulfate in the 

 Colon. Note the differences in absorption of X rays by skeleton (vertebrae, sacrum, ribs, 

 etc.), soft tissue (bottom edge of kidney, psoas muscle, liver), and gas pockets in stomach 

 and colon. Low contrast film. 



Optical Microscope 



The small object to be viewed is illuminated either from above or below. 

 In the former case reflected light, and in the latter case transmitted light, is 

 allowed to pass through a convex objective lens of short focal length. In 

 passing through the objective, the rays (visible region) are sharply bent, so 



