Concept explainers
where n is the index of refraction of the water. (Hint: Use the inverse Lorentz velocity transformation and note that the speed of light with respect to the moving frame is given by c/n.) (b) Show that for v << c, the preceding expression is in good agreement with Fizeau’s experimental result:
This proves that the Lorentz velocity transformation and not the Galilean velocity transformation is correct for light.
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Modern Physics
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- (i) Does the speed of an electron have an upper limit? (a) yes, the speed of light c (b) yes, with another value (c) no (ii) Does the magnitude of an electrons momentum have an upper limit? (a) yes, mec (b) yes, with another value (c) no (iii) Does the electrons kinetic energy have an upper limit? (a) yes, mec2 (b) yes, 12mec2 (c) yes, with another value (d) noarrow_forwardA spacecraft moves at a speed of 0.900c. If its length is L as measured by an observer on the spacecraft, what is the length measured by a ground observer?arrow_forward(a) All but the closest galaxies are receding from our own Milky Way Galaxy. If a galaxy 12.0x109ly away is receding from us at 0.900c, at what velocity relative to us must we send an exploratory probe to approach the other galaxy at 0.990c as measured from that galaxy? (b) How long will it take the probe to reach the other galaxy as measured from Earth? You may assume that the velocity of the other galaxy remains constant. (c) How long will it then take for a radio signal to be beamed back? (All of this is possible in principle, but not practical.)arrow_forward
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