The angle of incidence is always larger than the critical angle of the core material with respect to its cladding. Even if the fibre is bent or twisted, the light can easily travel through the fibre. The critical angle formula is a fundamental concept in optics. It enables us to calculate the critical angle, beyond which total internal reflection occurs. Critical Angle and Total Reflection Look at the given picture. Rays with different angles coming from the source at the bottom of the water filled glass, refracted from the surface, reflected and directly pass to the second medium without any reflection and refraction. In the previous section we learned Snell’s law of refraction. According to this law; reflecting, refracting or directly passing of light to the other medium is depends on angle of incident ray and refractive indexes of the ... Learn what critical angle is, how to calculate it, and why it is important for total internal reflection. Find out the critical angle values for different pairs of media and their applications in physics and chemistry.
