Acceptance angle | Numerical aperture | Optical fibre | 12 Physics| Samacheer kalvi.

12 Physics Samacheer kalvi Ln.6 Ray Optics Acceptance angle and numerical aperture in optical fibre. Optical fibre is based on the principle of total internal reflection.. It consists of inner part called core and outermost part called cladding. The refractive index of core must be greater than that of cladding then only total internal reflection takes place. For total internal reflection to takes place, the optical fibre must satisfy the two conditions 1) Light must travel from denser to rarer medium. 2) The angle of incidence in the denser medium must be greater than critical angle.