Calculate index of refraction with n = c/v from the speed of light in a medium, find v = c/n, or solve Snell’s law for an angle of refraction or index.
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Index of Refraction Formula
The formula for calculating a refractive index from wave speed is as follows:
- Where n is the index of refraction
- c is the speed of light in a vacuum = 299,792.458 km/s (299,792,458 m/s)
- v is the speed of light in a given medium
To calculate an index of refraction, divide the speed of light in a vacuum by the speed of light in the medium.
Index of Refraction Definition
An index of refraction is the ratio of the speed of light through a vacuum with respect to the speed of light through some other medium, such as water.
How to calculate index of refraction?
How to calculate index of refraction?
- First, determine the speed of light in a vacuum.
The speed of light in a vacuum is known to be 299,792.458 km/s (299,792,458 m/s).
- Next, measure the speed of light in the medium.
For example, the speed of light through water is about 225,000 km/s (for n ≈ 1.33).
- Finally, calculate the index of refraction.
Using the formula above and values from steps 1 and 2, calculate the index of refraction.
FAQ
An index of refraction is the ratio of the speed of light through a vacuum with respect to the speed of light through some other medium, such as water.
