| dc.description.abstract | X-rays were discovered in 1895 by the German physicist Röntgen [1]1 and were so named because their nature was unknown at the time.Unlike ordinary light,these rays were invisible, but they traveled in straight lines and affected photographic film in the same way as light.On the other hand,they were much more penetrating than light and could easily pass through the human body, wood, quite thick pieces of metal,and other “opaque”objects. It is not always necessary to understand a thing in order to use it,and x-rays were almost immediately put to use by physicians and,somewhat later,by engineers,who wished to study the internal structure of opaque objects. By placing a source of xrays on one side of the object and photographic film on the other,a shadow picture, or radiograph, could be made, the less dense portions of the object allowing a greater proportion of the x-radiation to pass through than the more dense. In this way the point of fracture in a broken bone or the position of a crack in a metal casting could be located. | en_US |
