If a material has an index of refraction of 2.25, what is the speed of light through it?

Asked on by lkehoe

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lemjay | High School Teacher | (Level 3) Senior Educator

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To solve, apply the formula of index of refraction which is:


n - index of refraction
c - velocity of light in a vacuum ( 3 x 10^8 m/s)  and
v - velocity of light in a medium

So, plug-in n=2.25 and c=3 x 10^8 to the formula.


Then, multiply both sides by v.

`2.25*v=(3xx10^8)/v * v`


And, divide both sides by 2.25.



Hence, the velocity of light in the medium is  `1.33xx10^8` m/s.

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