There are many different types of Energy that come from the SUN All of the types of energy travel in waves with different wavelengths. All type of energy are part of the Electromagnetic Spectrum 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju The energy is called Electromagnetic because the waves have electrical and magnetic features. The Spectrum usually divided into SEVEN parts 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju Common properties of Electromagnetic Spectrum All are transverse waves All travel at the same speed i.e., 3 x 108ms-1 in a vacuum All can travel through a vacuum They exhibit the properties of reflection and refraction EM waves can be described as vibrating electric and Magnetic fields 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju Increasing Frequency RADIO MICROWAVES INFRA RED VISIBLE ULTRA VIOLET X RAYS GAMMA RAYS Increasing Wavelength 28 November 2018 www.myphysicsnotes.com David Raju

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www.myphysicsnotes.com David Raju 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 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 1. Radio waves Radio waves are: Detected by aerials Used for communication 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 1. Radio waves Radio waves are: Detected by aerials Used for communication These waves are used to bring you the tunes from your favorite radio station, but they are also of radiation from the Sun with long wavelengths. 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 1. Radio waves 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. 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 2. Microwaves Microwaves can be demonstrated in the laboratory with the apparatus shown above and can be: Reflected by metal plates refracted by wax Diffracted by the gap between two metal plates 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 2. Microwaves Microwaves are: Detected by aerials Used for Communication 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 2. Microwaves These waves can be used to study the Universe , Communicate with satellites and for cooking 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 2. Microwaves 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 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 2. Microwaves Scientists believe that microwaves used by mobile phones can cause heating of cells and lead to permanent damage. 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 3.Infra Red Radiations Infra Red Radiation is: Emitted by: Hot objects 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 3.Infra Red Radiations Infra Red Radiation is: Emitted by: Hot objects Detected by: Skin Thermometers Photographic Film Used for: VCR/DVD controllers cooking 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 3.Infra Red Radiations 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 28 November 2018 www.myphysicsnotes.com David Raju

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www.myphysicsnotes.com David Raju 3.Infra Red Radiations Infra Red Radiation can be: Reflected by glass and so warms the interior of glass houses 28 November 2018 www.myphysicsnotes.com David Raju

Red, orange, yellow, green, blue, indigo violet 4.Visible Radiation 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 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 4.Visible Radiation The Visible Spectrum 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 5.Ultraviolet Radiation Ultra Violet Radiation is: Emitted by: Hot objects Detected by: The skin Photographic Film Fluorescent paints Used for: Sun beds 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 5.Ultraviolet Radiation Ultra Violet Radiation is: Emitted by: Hot objects Detected by: The skin Photographic Film Fluorescent paints Used for: Sun beds Security 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 5.Ultraviolet Radiation Emitted by: Hot objects Detected by: The skin Photographic Film Fluorescent paints Used for: Sun beds Security Hardening adhesives Sterilisation of surgical instruments 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 6.X-ray Radiation X ray beam copper anode filament heavy metal target electron beam H.T vacuum X – Rays are: Emitted by: atoms Detected by: Photographic Film Wilhelm Konrad Roentgen 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 6.X-ray Radiation Used for: X-ray photographs in medicine Detecting faults in metals and concrete 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 6.X-ray Radiation X-Rays X ray beam copper anode filament heavy metal target electron beam E.H.T vacuum 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 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 7.Gamma-ray Radiation Gamma Radiation is: Emitted by: nuclei Detected by: Photographic Film Geiger-Muller tubes 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 7.Gamma-ray Radiation 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 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju A Electromagnetic Wave Electric field Magnetic field e.m. radiation 28 November 2018 www.myphysicsnotes.com David Raju

www.myphysicsnotes.com David Raju 28 November 2018 www.myphysicsnotes.com David Raju