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| | radiometer experiment (Site not responding. Last check: ) |
 | | Could you please explain if the movement of the blades in a radiometer is due to the light or the heat produced by the light. |
 | | When a gas molecule comes into contact with one of the vanes, it rebounds more strongly from a fl face than from a bright face (because it gains more energy from a warmer face than a cooler face); as a result of many such rebounds, the vanes rotate, with the bright faces leading. |
 | | It is true that light striking an object does give some momentum to that object, but the amount is extremely tiny; furthermore, if the radiometer's movement were due to this "light pressure", the vanes would spin with the fl faces, not the bright faces, leading. |
| www.newton.dep.anl.gov /askasci/phy99/phy99182.htm (223 words) |
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