2006-09-19 13:51:44 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Physics
186,284 miles/second
2006-09-19 13:53:58 · answer #1 · answered by keepsondancing 5 · 0⤊ 0⤋
In metric units, c is exactly 299,792,458 metres per second (or 1,079,252,848.8 km/h). Note that this speed is a definition, not a measurement, since the fundamental SI unit of length, the metre, has been defined since October 21, 1983 in terms of the speed of light: one metre is the distance light travels in a vacuum in 1/299,792,458 of a second. Converted to imperial units, the speed of light is approximately 186,282.397 miles per second, or 670,616,629.384 miles per hour.
2006-09-19 13:55:34 · answer #2 · answered by eric l 6 · 0⤊ 0⤋
all the answers above give the speed of light in a vacuum, but light actually slows down when it is travelling through different substances.
2006-09-19 14:12:36 · answer #3 · answered by Adam 4 · 0⤊ 0⤋
the speed of light is 300000000 m/sec.
2006-09-19 14:01:06 · answer #4 · answered by Anonymous · 0⤊ 0⤋
about 186,282 miles per second, or about 300,000 km per second
2006-09-19 13:54:21 · answer #5 · answered by holden 4 · 0⤊ 0⤋
Really fast.
2006-09-20 14:05:00 · answer #6 · answered by TiM 4 · 0⤊ 0⤋
299,792,458 metres per second
2006-09-19 14:02:48 · answer #7 · answered by Den P 3 · 0⤊ 0⤋
it's 186,282.397 mi.'s per second
2006-09-19 14:08:11 · answer #8 · answered by dogpatch USA 7 · 0⤊ 0⤋
186000mps
2006-09-19 13:54:14 · answer #9 · answered by bayareart1 6 · 0⤊ 0⤋