Enemy or foe is an individual or a group that is seen as forcefully adverse or threatening. The concept of an enemy has been observed to be basic for both individuals and communities.
A diffractometer (pronunciation: di-frak-'tÃ¤-m&-t&r) is a measuring instrument for analyzing the structure of a material from the scattering pattern produced when a beam of radiation or particles (such as X-rays or neutrons) interacts with it. Principle
See Length, Light, Physical measurement, Wavelength standards. Wavelength values to an accuracy of 1 part in 10 5 can be determined with a spectrometer, spectrograph, or monochromator, in which a prism or diffraction grating is used as a dispersive element.