JAMB - Physics (2001 - No. 40)
If ray travelling in air is incident on a transparent medium as shown in the diagram, the refractive index of the medium is given as
cosα / sinβ
sinα / sinβ
cosβ / sinα
sinβ / sinα
ব্যাখ্যা
\(n = \frac{sin i}{sin r}\)
\(i = 90 - \alpha\)
\(\therefore n = \frac{sin 90 - \alpha}{sin \beta}\)
⇒ \(n = \frac{cos \alpha}{sin \beta}\)