Light and waves Flashcards
What is the refractive index?
How much a medium alters the speed of light
How do optical fibres work?
Total internal reflection-
The core of fibre is made out of glass with a high refractive index, whilst the cladding is made out of glass with a low refractive index.
Light entering the core is at an angle greater than the critical angle so TIR occurs.
Uses of optical fibers
Endoscopy
Communication
Difference between real image and virtual image
A real image can be formed on screen while a virtual image cannot
Use of radiowaves
Communication
Radio
Use of microwaves
Cooking
Satelite communication
Use of infrared
Cooking
Remote controls
Use of visible light
Viewing objects
Photography
Use of UV
Fluorescent lamps
Detecting forged banknotes
Uses of X-ray
Viewing the internal structure of objects
In medicine, for imaging
Use of gamma
Kill cancer cells
Sterilize surgical equipments
Danger of Infrared
Causes skin burns
Danger of UV
Skin cancer
What do the waves have in common?
Transverse waves
Travel at the same speed in a vacuum
Can be reflected, refracted, and diffracted
Ultrasound
A longitudinal sound wave, which is above the range of human hearing above 20 000Hz
