If light moves at a speed of 299,792,458 m/s, how long will it take light to move a distance of 1,000 km
The Correct Answer and Explanation is:
To determine how long it will take for light to move a distance of 1,000 kilometers, we can use the basic formula for time:
[
\text{Time} = \frac{\text{Distance}}{\text{Speed}}
]
Given:
- Speed of light = 299,792,458 m/s
- Distance = 1,000 kilometers = 1,000,000 meters (since 1 km = 1,000 meters)
Now, we can substitute the given values into the formula:
[
\text{Time} = \frac{1,000,000 \, \text{meters}}{299,792,458 \, \text{m/s}}
]
Calculating this:
[
\text{Time} \approx 3.34 \times 10^{-3} \, \text{seconds}
]
This means it will take approximately 3.34 milliseconds for light to travel 1,000 kilometers.
Explanation
The speed of light, 299,792,458 meters per second, is one of the fundamental constants of nature and represents the fastest speed at which information or matter can travel in the universe. To calculate the time it takes for light to cover a specific distance, we simply use the formula for time, which is the distance divided by the speed.
The units of distance and speed must match for this formula to work correctly, so we convert kilometers to meters (1 km = 1,000 meters) in this case. With the distance now expressed in meters, we can divide the total distance by the speed of light.
The result, 3.34 milliseconds (or about 3.34 thousandths of a second), indicates how quickly light can travel a relatively long distance, showing just how fast the speed of light is. This also provides insight into the nature of light and its behavior over large distances, especially when dealing with astronomical scales where light takes minutes, hours, or even years to reach us from distant stars or galaxies.