Refractive index (in terms of relative speeds) Total internal reflection (relationship between critical angle and refractive index) Transmission of light through optical fibres Lenses (how images are formed) Power of lenses Two lenses in contact The eye (optical structure, short sight, long sight and corrections)
MANDATORY EXPERIMENTS:
16. Verification of Snell’s law of refraction 17. Measurement of the refractive index of a liquid (or solid) 18. Measurement of the focal length of a converging lens
ACTIVITIES:
Demonstration of laws of refraction Demonstration of total internal refraction Simple exercise on lenses by ray-tracing or use of formula
SCIENCE, TECHNOLOGY AND SOCIETY:
Practical examples of laws of refraction (real and apparent depth of fish in water) Examples of total internal reflection (reflective road signs, mirages, prism reflectors and fibre optics) Uses of lenses (magnifying glasses, spectacles)
PHYSICAL QUANTITIES INTRODUCED IN THIS CHAPTER: Quantity
angle of refraction refractive index critical angle
power of a lens
Symbol r
n
C P
Name of SI unit degree
no unit degree
per metre
Symbol for unit
m1
Power of two lenses in contact Focal length of two lenses in contact
