The excess energy associated with this excited state is released when the nucleus emits a photon in the -ray portion of the electromagnetic spectrum.Most of the time, the -ray is emitted within 10Nuclides with atomic numbers of 90 or more undergo a form of radioactive decay known as spontaneous fission in which the parent nucleus splits into a pair of smaller nuclei.On Thursday, September 19, 1991, at about 1.30 p.m.on a sunny afternoon Erika and Helmut Simon, from Nuremberg in Germany, were enjoying the last day of a vacation half-walking and half-climbing through difficult icy and rock-strewn terrain high up on a mountain overlooking the Ötz valley in the Alpine borderlands between Austria and Italy.Shorter than violet you would see the ultraviolet, that which gives us tans and sunburns, and then you would encounter much more dangerous X-ray radiation and finally deadly gamma rays.Except for the energy they carry, all portions of the spectrum -- ordinary light, infrared, radio, ultraviolet -- are fundamentally the same.The product of this reaction can be predicted, once again, by assuming that mass and charge are conserved. They rapidly lose their kinetic energy as they pass through matter.As soon as they come to rest, they combine with an electron to form two -ray photons in a matter-antimatter annihilation reaction.-decay are often obtained in an excited state.
Here we examine the principal way in which astronomers have learned so much about the stars. Pass sunlight through a triangular prism or bounce it off the finely grooved surface of a compact audio disk and see it break merrily into a band of pure sparkling color, its "spectrum," familiar in the colors of a rainbow, in light glittering from newly fallen snow, in the rings and haloes around a partly- clouded Sun and Moon, in the flash of a cut diamond, and in so many other facets of nature.
Electron capture leads to a decrease of one in the charge on the nucleus.
The energy given off in this reaction is carried by an x-ray photon, which is represented by the symbol hv, where h is Planck's constant and v is the frequency of the x-ray.
Alpha decay of the The sum of the mass numbers of the products (234 4) is equal to the mass number of the parent nuclide (238), and the sum of the charges on the products (90 2) is equal to the charge on the parent nuclide.
Nuclei can also decay by capturing one of the electrons that surround the nucleus.