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Unformatted text preview: interact with a thin layer of lead and not be able to pass through it. In fact, even a piece of paper should stop an α-particle. 3 There are two isotopes or uranium, U-235 and U-238. What is the main diﬀerence between them ? The main diﬀernece between them is their number of neutrons. U-235 has 143 neutrons and U-238 has 146 neutrons. They both have the same number of protons, which is 96. Both are alpha particle emitters, that is they decay by emitting an α-particle. The half life of U-235 is roughly 700 million years while U-238 is roughly 4.4 billion years which makes a great isotope for dating the age of earth. 1...
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This note was uploaded on 05/18/2008 for the course PHY 102 taught by Professor Simoncatterall during the Spring '08 term at Syracuse.
- Spring '08