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37 Cards in this Set
- Front
- Back
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J. J Thomson |
studied the properties of cathode rays |
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Wilhelm Roentgen |
discovered x-rays |
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Henri Becquerel |
dsicovered natural radioactivity in Uranium |
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Ernest Rutherford |
discovered alpha, beta, and gamma radiation |
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Enrico Fermi |
produced the first controlled fission reaction |
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Albert Einstein |
developed the special theory of reletivity |
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Max Planck |
developed the quantum theory of matter and energy |
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Arthur Compton |
showed that cosmic rays are charged particles |
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J. Robert Oppenheimer |
directed project to build first atomic bomb |
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cathode rays |
streams of high- speed electrons emitted from a high-voltage discharge tube |
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x-rays |
electromagnetic waves released when electrons strike a metal target |
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radioactive elements emit |
1. high speed particles 2. energetic electromagnetic waves |
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alpha particle |
high-speed helium nucleus emitted from the nucleus of a radioactive element |
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beta particle |
high- speed electron emitted from the nucleus of a radioactive element |
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gamma ray |
high- speed electromagnetic wave emitted from the nucleus of a radioactive element |
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cosmic rays |
high- speed charged particles that strike earths atmosphere from outer space |
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3 kinds of spectra discovered by Gustav Kirchoff and Robert Bunsen |
1. continuos 2. emission 3. absorption |
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photoelectric effect |
the emission of electrons caused by light falling upon the surface of certain metals |
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photon |
discrete bundle of light energy |
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which properties of light determine the number of photons and their energy levels |
brightness frequency |
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quantum |
discrete bundle of energy |
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3 ideas and discoveries made in physics between 1895 and 1905 |
1. electrons 2. x-rays 3. radioactive elements |
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difference between modern physics and classical physics |
modern takes the quantum theory into account classical does not use the quantum theory |
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what determines physical properties? |
the number of protons and nuetrons in an atom |
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physical properties are determined by |
the number of protons and nuetrons in an atom |
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chemical properties are determined by |
the number of electrons in each atom and their placement in orbitals |
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atomic number of an atom is determined by |
the number of protons in its nucleus |
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atomic number |
identifies elements exactly |
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isotopes |
atoms with the same number of protons but different number of nuetrons |
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radioactivity |
the emission of particles or rays from the nucleus of an atom |
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radioactivity decay can make what three kinds of fundamental changes in atoms? |
1. in atomic mass 2. in atomic number 3. in energy content |
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half-life |
the amount of time required for half of a given sample of a radioactive element to undergo radioactive decay |
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fission |
the splitting of a heavy nucleus into 2 nuclei of medium weight |
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chain reaction |
any process in which the material that starts the reaction is also one of the products |
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fusion |
a nuclear reaction in which two light weight nuclei combine to form a massive nucleus with the simultaneous release of energy |
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special theory of relativity concludes that |
energy and mass are interchangeable |
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formulas |
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