Optics

When light reflects off curved and smooth surfaces, particularly from a convex surface, the light rays diverge after reflection. This is called convex reflection. In contrast, concave surfaces cause light rays to converge. Convex surfaces are those that curve outward, like the surface of a sphere, which results in light spreading out after reflection.

Step 1: Understanding optical fiber working principle
Optical fibers work by guiding light through a thin glass or plastic core surrounded by cladding with a lower refractive index. The key phenomenon that enables this is total internal reflection.
Step 2: Total internal reflection condition
Total internal reflection occurs when: 1. Light travels from a denser medium (higher refractive index) to a rarer medium (lower refractive index) 2. The angle of incidence is greater than the critical angle
Step 3: Application in optical fibers
- The core has higher refractive index than cladding - Light entering at proper angles undergoes repeated total internal reflections - This allows light to travel long distances with minimal loss
Why other options are incorrect:
(a) Interference - not the primary principle used
(c) Diffraction - causes signal dispersion, which is undesirable
(d) Scattering - causes signal loss, not the desired effect