Topic 6 Refraction of Light Light has particle characteristics and behaves like waves. It is a member of the electromagnetic spectrum.

contents  Reflection of Light  Refraction of Light  Total Internal Reflection  Lenses  Chapter Review  Reflection of Light  Refraction of Light  Total Internal Reflection  Lenses  Chapter Review

refraction of light Exercise water air Incident ray water glass Incident ray air glass Incident ray

Ruler in water

Thermometer in water

total internal reflection For total internal reflection to occur  the light ray must travel from an optically denser medium towards a less dense medium  the angle of incidence must be greater than the critical angle For total internal reflection to occur  the light ray must travel from an optically denser medium towards a less dense medium  the angle of incidence must be greater than the critical angle total internal reflection Note: optically denser medium has a higher refractive index n

total internal reflection Exercise water air Incident rays critical angle c of water = 48.7° 41.3° 48.7° 40° 41.3° < c 48.7° 50° > c 50° Total internal reflection

total internal reflection n = sin c 1  relationship between refractive index and critical angle is

Optic fibre

Light enters the core (optically denser) and it reaches the cladding (less dense) at an  >critical angle c. Total internal reflection occurs. cladding core  

FIRBE OPTICS 1.Installation of optical fibre at HDB flat 2. Next Generation Nationwide Broadband Network