PS: препод придирчивый, гугл переводчик не прокатит(
2. Roentgen also revealed that these X-rays could pass through solid matter and expose an X-ray film. This discovery led immediately to the use of X-rays in medicine, a use we are all familiar with.
3. Although Roentgen discovered the properties of X-rays he did not know what the rays were. He therefore called them X-rays, the X standing for their unknown nature. Today scientists know X-rays to be electromagnetic radiation of extremely high frequency and therefore of extremely short wave length. X-rays are considered to be produced whenever rapidly moving electrons bombard any solid material. The greater the atomic weight of the material, the more plentiful the X-rays, the greater the speed of the electrons the higher the frequency of the X-rays.
4. As mentioned above X-rays have been in a wide use for diagnostic purposes in medicine since their discovery. Industrial radiology was discovered later particularly for inspecting welds and castings in the automobile and airplane industries. Flaws and cracks inside the metal are readily revealed due to the use of X-ray techniques. Famous paintings are often X-rayed to determine whether they are the originals or forgeries.