Physics
Speed of Light Calculator
Find the time for light to travel a given distance.
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Light travels at almost 300,000 km/s — this finds how long it takes to cover a distance.
The math behind it
t = distance ÷ c, with c = 299,792.458 km/s in a vacuum.
Worked Example
To the Moon (384,400 km) → about 1.28 s.Frequently Asked Questions
Does light slow in glass?
Yes — its speed drops by the refractive index of the medium.
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