The phenomenon of radioactivity was observed by a scientist “Henry Bacquaral”. He studied that some elements like Uranium and Radium causes the photographic plate to “Fog” even when the plate is covered with blue paper later on the phenomenon was clearly explained by “Curie” brothers. Who observe the emission as similar in the properties define by Henry Bacqaral.
The spontaneous emission of invisible radiations from elements having atomic number greater than 82 due to enthalpy of atomic nuclei is called “Radioactivity”. The elements are called radioactive elements. While the rays are called radioactive rays.
DISCOVERY OF RADIOACTIVITY
Radioactivity and Radioactive rays are discovered by a simple experiment in which a radioactive element is placed in the lead block open from only end. There is a photographic plate placed above the block to observe the emission of radiation, while electrical field is also applied to observe the nature of radioactive rays.
The spots produced on photographic plate suggest that there are three types of radioactive radiations. Those rays moving towards -ve side of electrical field are, +ve in Nature called or – rays, rays moving towards positive end of field are -ve and called ß-rays while those rays moving straight not effected by field are considered as neutral rays called y – rays. essaynara.com/