>Our apparatus comprises of a Perspex tube which is wound into a coil with a single turn.
The diameter of the coil is about 120 mm.
The diameter of the Perspex tube is about 8 mm.
The entire set up is fitted on a wooden board and comes with a laser source.
Our apparatus demonstrates total internal reflection as light entering from one end seems to twist with the tube and (mostly) only exits at the far end.
Thus, with this simple apparatus, students can easily comprehend the basic phenomenon of total internal reflection that finds practical application in fiber optics.
Fiber optics employ the same principle of the transmission of light down fibers of plastic or glass. Because the fibers are thin, light entering is likely to strike the inside surface at an angle greater than the critical angle and, thus, be totally reflected.