Answer:
n₁ must be greater than n₂ in order for total internal reflection to be possible.
Explanation:
From Snell's law:
[tex] n_{1}sin(\theta_{1}) = n_{2}sin(\theta_{2}) [/tex]
We have that total internal reflection is produced when the angle of refraction is 90°, so the incident angle becomes the critical angle.
Now, the snell's equation will be:
[tex]n_{1}sin(\theta_{c}) = n_{2}sin(90)[/tex]
[tex]\theta_{c} =sin^{-1}(\frac{n_{2}}{n_{1}})[/tex]
It will be possible just if n₁ > n₂.
Therefore, the index of refraction of the first medium (n₁) must be greater than the index of refraction of the second medium (n₂) in order for total internal reflection to be possible.
I hope it helps you!
