ELECTROMAGNETIC WAVES

ELECTROMAGNETIC WAVES

1. RADIO WAVES

   • WAVELENGTH : 1cm to 10Km
   • SOURCES
     • Produced due to oscillations of electrons in antennas
   • DETECTION
     • TV and radio receivers
   • USES
     • In TV and radio telescope

2. MICROWAVES

   • WAVELENGTH : 3cm
   • SOURCES
     • Magnetron, Klystron, and the Sun
   • DETECTION
     • Micro wave linked dish and dish antenna
   • USES
     • Radar, live TV links, satellite communications

3. VISIBLE LIGHT

   • WAVELENGTH : 10^-7 m
   • SOURCES
     • Hot objects (filament lamp), the Sun
   • DETECTION
     • Eye, photoelectric cell, photographic film, solar panels
   • USES
     • For visibility

4. INFRARED RADIATIONS

   • WAVELENGTH : 10^-3 m to 10^-6 m
   • SOURCES
     • Warm objects, the Sun
   • DETECTION
     • Skin, phototransistor, night vision glasses, solar water heater, some photographic films
   • USES
     • Night vision, infrared photography is safer alternative to x-ray photography to detect blocked arteries and cancer

5. UV

   • WAVELENGTH : 10^-8 m
   • SOURCE
     • Very hot objects, the Sun
   • DETECTION
     • Photo electric light meter, fluorescent substance, some photographic films
   • USES
     • Causes sun-tan, produces vitamins in skin, detects forged bank notes, in washing powder to kill bacteria

6. X RAYS

   • WAVELENGTH : 10^-9 m
   • SOURCE
     • X-ray tube (by rapid deceleration of electrons
   • DETECTION
     • GM Tube, some photographic films
   • USE
     • To take x-rays, for luggage checking

7. GAMMA RAYS

   • WAVELENGTH : 10^-12 m
   • SOURCE
     • Nuclear vibrations in radioactive substance
   • DETECTION
     • GM Tube, photographic films
   • USE
     • To treat cancer, sterilize food, detect leaks in underground pipes, find age of rocks and bones