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Jean-Bernard-Léon Foucault, not Armand Fizeau, is the physicist credited with measuring the speed of light. However, I can provide information about Armand Fizeau, who made significant contributions to the study of optics and the measurement of the speed of light.

Armand Fizeau was a French physicist and photographer born on September 23, 1819, in Paris, France. He is best known for his work in optics, particularly his experiments related to the speed of light and the Doppler effect.

Fizeau’s most notable accomplishment was his successful determination of the speed of light using a method called the Fizeau apparatus. In 1849, he directed a beam of light at a rotating cogwheel with a toothed gap. A mirror reflecting the beam was placed several kilometers away, and the returning light passed through the gap in the wheel before reaching the observer. By adjusting the speed of the wheel rotation, Fizeau was able to find the critical rotation speed at which the returning light beam would be completely blocked. Using this information and the known distance, he was able to calculate the speed of light accurately.

Regarding his personality, Fizeau was known to be an ambitious and meticulous scientist. He possessed a great passion for experimental physics and had a strong desire to understand the fundamental laws of nature. Fizeau was dedicated to conducting precise and rigorous experiments to advance scientific knowledge.

In addition to his work on the speed of light, Fizeau made important contributions to the study of the Doppler effect. He conducted experiments to measure the shift in the frequency of light when the source or observer is in motion relative to each other. Fizeau’s experiments helped refine our understanding of the Doppler effect and its application in various fields of science.

Overall, Armand Fizeau was a determined and accomplished scientist who significantly contributed to the fields of optics, the measurement of the speed of light, and the study of the Doppler effect.」