How long does it take light to travel one centimeter?

Answer 1

Short answer: About 33.3 picoseconds (in vacuum).

The speed of light in a vacuum is 2.9979 x 10^8 meters per second. Written in centimeters, this is 29,979,000,000 centimeters per second.

That is just almost 30 Billion centimeters per second. So, in one-Billionth of a second light travels 30 centimeters (in vacuum). (More precisely, it travels 29.979 cm per billionth of a second, but 30 cm is a very good approximation.)

Okay, now for the 1 cm time: divide one-billionth of a second by 30, and we get 33.3 Trillionths of a second (3.33 x 10^-11 sec, or 33.3 picoseconds.)

If the light is traveling in some medium other than vacuum, then it goes at a slower speed. We typically use 'c' to represent the speed of light in a vacuum. If the light travels at speed 'v' in a medium, then we call the Refractive Index of the medium n, where n = c/v. For example, pure water has n = 1.33, common glass has n = 1.5.

[The refractive index depends upon the wavelength of the light. Germanium crystal has the highest refractive index among common, natural material; it is opaque to visible light but in the mid infrared it has n = 4.]

Answer 2

At 20 degrees Celsius sound travels at 343 m/s (because: speed of sound= 331+ temperature*0.6). This means that it takes 1 second for sound to travel 34300 centimeters. If you take the inverse of this (1/34300=0.000029) then you'll see that it takes 0.000029 seconds for sound to travel 1 cm. You then multiply this number by the speed of sound (3e8m/s), and you have your answer: 8746.36 meters.

Answer 3

Speed of sound = 340 meters per second.

Time for one meter = 1/340 second

Speed of light = 299792458 meters per second

Distance in 1/340 second = 299,792,458 / 340 =

-- 881.7 kilometers (rounded)

-- 547.9 miles (rounded)

Answer 4

Speed of sound in air is c ≈ 331 + 0.6 × T.

T = Temperature in °C.

Speed of sound in air at 20°C is c ≈ 331 + 0.6 × 20 = 343 m/s.

Answer 5

The speed of sound is 343.2 meters a second, now you can do the math.

Answer 6

One thirtieth of a billionth sec