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For example, for visible light, the refractive index of glass is typically around 1.5, meaning that light in glass travels at c / 1.5 ≈ 200 000 km/s (124 000 mi/s); the refractive index of air for visible light is about 1.0003, so the speed of light in air is about 90 km/s (56 mi/s) slower than c.
6.7 × 10 −7 to 2.5 × 10 −5: 1 × 10 −15 to 3.7 × 10 −14: Calculated speed of an amoeba. [5] 10 −6: 1.52 × 10 −6: 5.4 × 10 −6: 3.4 × 10 −6: 5.1 × 10 −15: Speed of a cellular vesicle propelled by a motor protein. [6] 10 −5: 1.02 × 10 −5: 3.67 × 10 −5: 2.28 × 10 −5: 3.40 × 10 −14: Speed of the tip of a 7 cm ...
A lightning flash preceding its thunder by one second would be approximately 343 m (0.213 miles) away; thus a delay of three seconds would indicate a distance of about 1 km (0.62 miles); while a flash preceding thunder by five seconds would indicate a distance of roughly 1 mile (1.6 km).
Immediate precautions against lightning should be taken if the F-B time is 25 seconds or less, that is, if the lightning is closer than 8 km or 5 miles. A 2014 report suggested that whether a person was standing up, squatting , or lying down when outside during a thunderstorm does not matter, because lightning can travel along the ground; this ...
A bolt of lightning that stretched nearly 500 miles across three U.S. states is the new world record holder for longest flash. The single flash extended 477.2 miles (768 kilometers) across Texas ...
The longest known lightning events have been given world-record status by the World Meteorological Organization, or WMO, in a recently published study. Study: World-record lightning flash was ...
The speed at which energy or signals travel down a cable is actually the speed of the electromagnetic wave traveling along (guided by) the cable. I.e., a cable is a form of a waveguide. The propagation of the wave is affected by the interaction with the material(s) in and surrounding the cable, caused by the presence of electric charge carriers ...
The number of yearly lightning deaths in the U.S. has been cut in half since 1996, but for Cooper, the next challenge is decreasing lightning deaths in developing countries where few lightning ...