Uses of Electromagnetic Waves

Question	Answer
Uses of Gammma Rays	Sterilization of medical equipment Radiotherapy (destroying cancer cells)
Why can Radio waves be received at long distances from the transmitter?	They reflect off the ionosphere
Uses of infrared	optical fiber communication thermal imaging
Uses of ultraviolet	security ink e.g. detecting forged bank notes
What do all EM waves have in common?	They travel at the same speed
Why are Fluorescent lamps not harmful to humans even though they emit ultraviolet radiation?	The radiation is absorbed by a coating on the inside of the glass that emits visible light instead
How does a camera create a photograph using visible light?	They focus light onto a photosensitive surface
How can the amount of light entering the camera be controlled?	how big the aperture is and how long the surface is exposed to light with shutter speed
What can X ray exposure lead to?	mutations cancer

Resource summary

	Created by Joanna van Dyk almost 8 years ago