How to find the speed of light?

Question

the average distance between the earth and the sun is 93 million miles. How would you find an approximate value for the amount of time it takes a light ray to travel from the sun to the earth?

Answer 1

Because of the huge distance, it takes a finite amount of time - just over 8 minutes - for light to get from the surface of the Sun and travel across space to reach the Earth. So when we look up at the Sun in the sky, we're not actually seeing the Sun as it appears now, we're looking at the light that left the Sun just over 8 minutes ago!

Answer 2

The Danish astronomer Ole Romer observed eclipses of Jupiter's satellite Io. He noticed that the interval between eclipses was extended when Earth was moving away from Jupiter and reduced when Earth was moving towards Jupiter. He deduced that the difference was caused by the finite speed of light. The accumulated delay when the Earth is on the far side of Jupiter amounts to 1000 seconds compared with when the Earth is nearest to Jupiter. This means that light takes 1000 seconds to cross the diameter of the Earth's orbit (186 million miles), therefore it takes 500 seconds to cross the radius of the Earth's orbit (93 million miles).

Answer 3

Light travels around 300,000,000 meters per second, or 300,000 kilometers per second.

Converted, the distance from the earth to sun at 93 million miles equals 150,000,000 kilometers.

So, divide the distance by the speed of light.

150 million km / 300,000 km/s = 500 seconds or 8 & 1/3 minutes or .138 hours

Answer 4

Distance to sun from earth = 93,000,000 miles (this varies but 93 million is an accepted average distance.)

Speed of light = 186,000 miles/seconds

Since velocity = distance/time or v = d/t  we can solve for t

namely t = d/v = 93,000,000/186,000 = 500 seconds = 8.333333333 minutes

Answer 5

Speed of Light is:

186282.3970512208701185079137835 Miles per second

93,000,000 divided by 186282.3970512208701185079137835= Seconds

= 499.24201895699457522710594674134 seconds

499.24201895699457522710594674134 divided by 60 = Minutes

= 8.3207003159499095871184324456883 Minutes

Rounded up = 8.32

8 Minutes and 32 seconds is your answer

In word:

Speed of light in miles per second

Divide the distance between the Earth and Sun by the

Speed of light in miles per second= Your answer in seconds

Your answer in seconds divided by 60 = Your answer in minutes

Your answer in minutes rounded up to the second decimal= Your appropriate answer which is; Eight Minutes and thirty-two seconds

Answer 6

Divide the distance by the speed of light.

Duh...

Answer 7

If you're actually trying to determine the speed of light, you can do this fairly easy with a fast microprocessor, an LED or laser, a light sensor, and a mirror.

If you set up the mirror at a few feet away, direct the LED/laser towards the mirror so it reflects back and is detected by the light sensor.  You can then set up the microprocessor to pulse the light and time how long it takes to see the resulting pulse.  This should give you a decently accurate speed of light in air.  You can do the experiment inside of a vacuum bell to get closer to the speed of light in a vacuum.

This is definitely the easiest way to determine the speed of light these days. :)

Answer 8

Light travels at about 300,000 km per second. That's fast! For comparison, at full speed Concorde flew at only about 0.75 km per second. Still, by Earth standards, the Sun is a long way away - about 150,000,000 km away (to place this in context, the distance between London and New York is about 5550 km).

Beacuse of the huge distance, it takes a finite amount of time - just over 8 minutes - for light to get from the surface of the Sun and travel across space to reach the Earth. So when we look up at the Sun in the sky, we're not actually seeing the Sun as it appears now, we're looking at the light that left the Sun just over 8 miniutes ago!

Dr Jim Wild - Lancaster University

Answer 9

speed = distance / time

Answer 10

well, you really can't find the speed of light because it goes so fast that it passes by the world in one second every time

Answer 11

If you want to find the amount of time it takes light to get from the Sun to the Earth, you need to know the speed of light.  Fortunately, the speed of light is defined as 2.99 x 10^8 m/s.  So take the distance in meters (not miles) and divide by the speed to get how long it takes (in seconds).  Google can do that and the conversions for you.

Answer 12

Photons travel at 299,792,458 m/s. At that speed it would take approximately 8 minutes and 20 seconds to travel the average distance of approximately 150,000,000 km from the Sun the Earth because the Earth's orbit around the Sun is elliptical.

And I suggest that you use metric units!

Answer 13

93,000,000 miles

______________

128,000 miles/second (speed of light)

= 727 seconds or about 12 minutes.  Though It's usually calculated to about 8 minutes