All waves in the Electromagnetic Spectrum Are transverse waves

1. All waves in the Electromagnetic Spectrum • Are transverse waves • Travel at the same speed ( 3 x 108ms-1 in a vacuum) • Can travel through a vacuum

2. Increasing Frequency RADIO MICROWAVES INFRA RED VISIBLE ULTRA VIOLET X RAYS GAMMA RAYS Increasing Wavelength

4. RADIO Wavelength: 1 m – 1500 m Source: Electronics Detector: Aerial Properties/uses: Radio communication TELEVISION Wavelength: around 50 cm Source: Electronics Detector: Aerial Properties/uses: Television MICRO WAVES Wavelength: 1 mm – 50 cm Source: Electronics Detector: Aerial Properties/uses: Microwave ovens, radio telescopes, radar INFRA RED Wavelength: 0.7-10 mm Source: Atoms Detector: Skin, thermometer, film Properties/uses: Physiotherapy, night sight, locating people trapped in smoke or ruins VISIBLE Wavelength: 0.4-0.7 mm Source: Atoms Detector: Eye, film Properties/uses: We use it to see the world around us ULTRA VIOLET Wavelength: 0.001 – 0.4 mm Source: Atoms Detector: Skin, film Properties/uses: Sun tan, sun burn, theatre, checking documents, microscopes X RAYS Wavelength: around 1 nm Source: Atoms Detector: Film Properties/uses: Medical X rays, defects in metals, checking paintings GAMMA RAYS Wavelength: around 1 pm Source: Nuclei Detector: Film, Geiger counter Properties/uses: Medical, sterilising food, checking metal castings, checking water flow

5. Radio Waves • Radio waves are: • Detected by aerials • Used for communication

6. Radio Waves • Radio waves are: • Detected by aerials • Used for communication • Long wavelength radio waves are: • Diffracted and so can be detected below the horizon and in the shadow of hills • Reflected by the ionosphere and so can be detected below the horizon

7. Microwaves • Microwaves can be demonstrated in the laboratory with the apparatus shown above and can be: • Reflected my metal plates • refracted by wax • Diffracted by the gap between two metal plates

8. Microwaves • Microwaves are: • Detected by aerials (diodes) • Used for • Communication

9. Microwaves • Microwaves are: • Detected by aerials (diodes) • Used for • Communication • Cooking • Short wavelength micro waves are: • Not diffracted and so can only be used for line of sight communication • Pass through the ionosphere and so can be used to communicate with satellites orbiting the Earth

10. Microwaves Scientists believe that microwaves used by mobile phones can cause heating of cells and lead to permanent damage.

11. Infra Red, IR • Infra Red Radiation is: • Emitted by: • Hot objects

12. Infra Red, IR • Infra Red Radiation is: • Emitted by: • Hot objects • Detected by: • Skin • Thermometers • Photographic Film • Used for: • VCR/DVD controllers • cooking • Infra Red Radiation can be: • Reflected by glass and so warms the interior of glass houses • Is radiated by the Earth into space and so cools the planet • Is reflected by carbon dioxide in the atmosphere and can lead to global warming

13. Infra Red, IR • Infra Red Radiation can be: • Reflected by glass and so warms the interior of glass houses

14. Infra Red, IR • Infra Red Radiation can be: • Reflected by glass and so warms the interior of glass houses • Is radiated by the Earth into space and so cools the planet • Is reflected by carbon dioxide in the atmosphere and can lead to global warming

15. The Visible Spectrum • Visible light is: • Emitted by: • Hot objects • Detected by: • The eye • Photographic Film • Used for: • seeing The visible spectrum White Light Red, orange, yellow, green, blue, indigo violet

16. The Visible Spectrum

17. Ultraviolet Radiation • Ultra Violet Radiation is: • Emitted by: • Hot objects • Detected by: • The skin • Photographic Film • Fluorescent paints • Used for: • Sunbeds

18. Ultraviolet Radiation • Ultra Violet Radiation is: • Emitted by: • Hot objects • Detected by: • The skin • Photographic Film • Fluorescent paints • Used for: • Sunbeds • Security

19. Ultraviolet Radiation • Ultra Violet Radiation is: • Emitted by: • Hot objects • Detected by: • The skin • Photographic Film • Fluorescent paints • Used for: • Sunbeds • Security • Hardening adhesives • Hardening fillings in teeth • Sterilisation of surgical instruments

20. vacuum E.H.T heavy metal target electron beam filament copper anode X ray beam X-Rays • X – Rays are: • Emitted by: • atoms • Detected by: • Photographic Film Wilhelm Konrad Roentgen

21. vacuum E.H.T heavy metal target electron beam filament copper anode X ray beam X-Rays • X – Rays are: • Emitted by: • atoms • Detected by: • Photographic Film • Used for: • X-ray photographs in medicine • Detecting faults in metals and concrete • Will: • Damage human cells which may kill them or mutate them, leading to cancer Wilhelm Konrad Roentgen

22. Gamma Radiation is: • Emitted by: • nuclei • Detected by: • Photographic Film • Geiger-Muller tubes Gamma Radiation

23. Gamma Radiation is: • Emitted by: • nuclei • Detected by: • Photographic Film • Geiger-Muller tubes • Used for: • Treating cancer • Detecting faults in metals and concrete • Sterilising surgical equipment • Killing bacteria on food • Will: • Damage human cells which may kill them or mutate them, leading to cancer Gamma Radiation

24. A Electromagnetic Wave Electric field Magnetic field e.m. radiation