source rotating toothed wheel (720 cogs) d=8,633 m observer Fizeau's experiment to measure the speed of light. mirror This wheel has only 70 teeth In 1849, the French physicist Hyppolyte Fizeau (1819-1896) made the first terrestrial measurement of the speed of light, in a simple but ingenious way. In Fizeau's experiment, light from a source was focused onto the rim of a rotating wheel, cut with very fine teeth. The light passing between the teeth was reflected from a mirror and retraced its path, as shown in the schematic diagram above. If the wheel was stationary or turning slowly, the light transmitted between any particular pair of teeth returned in time to pass through the same gap. As the rotational speed of the wheel was increased, the adjacent tooth began to move into the position previously occupied by the gap, blocking some of the light. The wheel contained 720 teeth and Fizeau saw the first eclipse when the wheel was rotating at 12.6 rev/s. Using the information provided, determine the speed of light based on Fizeau's measurements.

source rotating toothed wheel (720 cogs) d=8,633 m observer Fizeau's experiment to measure the speed of light. mirror This wheel has only 70 teeth In 1849, the French physicist Hyppolyte Fizeau (1819-1896) made the first terrestrial measurement of the speed of light, in a simple but ingenious way. In Fizeau's experiment, light from a source was focused onto the rim of a rotating wheel, cut with very fine teeth. The light passing between the teeth was reflected from a mirror and retraced its path, as shown in the schematic diagram above. If the wheel was stationary or turning slowly, the light transmitted between any particular pair of teeth returned in time to pass through the same gap. As the rotational speed of the wheel was increased, the adjacent tooth began to move into the position previously occupied by the gap, blocking some of the light. The wheel contained 720 teeth and Fizeau saw the first eclipse when the wheel was rotating at 12.6 rev/s. Using the information provided, determine the speed of light based on Fizeau's measurements.