Electromagnetic Spectrum 19 May 2015 All waves in the Electromagnetic Spectrum Are transverse waves Travel at the same speed ( 3 x 10 8 ms -1 in a vacuum) Can travel through a vacuum

Electromagnetic Spectrum 19 May 2015 RADIOMICROWAVESINFRA REDVISIBLE ULTRA VIOLETX RAYS GAMMA RAYS Increasing Wavelength Increasing Frequency

Electromagnetic Spectrum 19 May 2015

Electromagnetic Spectrum 19 May 2015 Wavelength: 1 mm – 50 cm Source: Electronics Detector: Aerial Properties/uses: Microwave ovens, radio telescopes, radar RADIO TELEVISION MICRO WAVES INFRA RED VISIBLE ULTRA VIOLET X RAYS GAMMA RAYS Wavelength: around 1 nm Source: AtomsDetector: Film Properties/uses: Medical X rays, defects in metals, checking paintings Wavelength: – 0.4  m Source: Atoms Detector: Skin, film Properties/uses: Sun tan, sun burn, theatre, checking documents, microscopes Wavelength:  m Source: AtomsDetector: Eye, film Properties/uses: We use it to see the world around us Wavelength: around 50 cm Source: Electronics Detector: Aerial Properties/uses: Television Wavelength: 1 m – 1500 m Source: Electronics Detector: Aerial Properties/uses: Radio communication Wavelength: around 1 pm Source: Nuclei Detector: Film, Geiger counter Properties/uses: Medical, sterilising food, checking metal castings, checking water flow Wavelength:  m Source: Atoms Detector: Skin, thermometer, film Properties/uses: Physiotherapy, night sight, locating people trapped in smoke or ruins

Electromagnetic Spectrum 19 May 2015 Radio Waves Radio waves are: Detected by aerials Used for communication

Electromagnetic Spectrum 19 May 2015 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

Electromagnetic Spectrum 19 May 2015 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

Electromagnetic Spectrum 19 May 2015 Microwaves are: Detected by aerials (diodes) Used for Communication Microwaves

Electromagnetic Spectrum 19 May 2015 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 Microwaves

Electromagnetic Spectrum 19 May 2015 Scientists believe that microwaves used by mobile phones can cause heating of cells and lead to permanent damage. Microwaves

Electromagnetic Spectrum 19 May 2015 Infra Red, IR Infra Red Radiation is: Emitted by: Hot objects

Electromagnetic Spectrum 19 May 2015 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

Electromagnetic Spectrum 19 May 2015 Infra Red, IR Infra Red Radiation can be: Reflected by glass and so warms the interior of glass houses

Electromagnetic Spectrum 19 May 2015 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

Electromagnetic Spectrum 19 May 2015 Red, orange, yellow, green, blue, indigo violet White Light The visible spectrum The Visible Spectrum Visible light is: Emitted by: Hot objects Detected by: The eye Photographic Film Used for: seeing

Electromagnetic Spectrum 19 May 2015 The Visible Spectrum

Electromagnetic Spectrum 19 May 2015 Ultraviolet Radiation Ultra Violet Radiation is: Emitted by: Hot objects Detected by: The skin Photographic Film Fluorescent paints Used for: Sunbeds

Electromagnetic Spectrum 19 May 2015 Ultraviolet Radiation Ultra Violet Radiation is: Emitted by: Hot objects Detected by: The skin Photographic Film Fluorescent paints Used for: Sunbeds Security

Electromagnetic Spectrum 19 May 2015 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

Electromagnetic Spectrum 19 May 2015 X ray beam copper anode filament heavy metal target electron beam E.H.T vacuum X-Rays X – Rays are: Emitted by: atoms Detected by: Photographic Film Wilhelm Konrad Roentgen

Electromagnetic Spectrum 19 May 2015 X ray beam copper anode filament heavy metal target electron beam E.H.T vacuum 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

Electromagnetic Spectrum 19 May 2015 Gamma Radiation Gamma Radiation is: Emitted by: nuclei Detected by: Photographic Film Geiger-Muller tubes

Electromagnetic Spectrum 19 May 2015 Gamma Radiation 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

Electromagnetic Spectrum 19 May 2015 Electric field Magnetic field e.m. radiation A Electromagnetic Wave