Electromagnetic Spectrum and Light

([b]EM Spectrum = Electromagnetic Spectrum[/b] & [b]EM = Electromagnetic[/b]) ([b]Electromagnetic Radiation is when EM waves carry energy[/b]) [h3]General properties of the EM Spectrum[/h3] [table] [tr] [td style='padding:10px;font-weight:400']Wave type[/td][td style='padding:10px;font-weight:400']Abbreviation[/td][td style='padding:10px;font-weight:400']Approximate Wavelength[/td] [/tr] [tr] [td]Radio Waves[/td][td style='background-color:#3C427C;color:#fff;']RW[/td][td]More than 1 metre[/sup][/td] [/tr] [tr] [td]Microwaves[/td][td style='background-color:#3C427C;color:#fff;']MW[/td][td]1mm to 1 metre[/td] [/tr] [tr] [td]Infra-Red[/td][td style='background-color:#3C427C;color:#fff;']IR[/td][td]7[multiply]10[sup]-7[/sup]m to 1mm[/td] [/tr] [tr] [td]Light Spectrum[/td][td style='background-color:#3C427C;color:#fff;padding:0 2px;']Visible Light[/td][td]4[multiply]10[sup]-7[/sup]m to 7[multiply]10[sup]-7[/sup]m[/td] [/tr] [tr] [td]Ultraviolet[/td][td style='background-color:#3C427C;color:#fff;']UV[/td][td]1[multiply]10[sup]-8[/sup]m to 4[multiply]10[sup]-7[/sup]m[/td] [/tr] [tr] [td]X-Rays[/td][td style='background-color:#3C427C;color:#fff;']X-Rays[/td][td]1[multiply]10[sup]-9[/sup]m to 1[multiply]10[sup]-8[/sup]m[/td] [/tr] [tr] [td]Gamma Rays[/td][td style='background-color:#3C427C;color:#fff;'][gamma] (Gamma)[/td][td]Less than 1[multiply]10[sup]-9[/sup]m[/td] [/tr] [/table] [b]Also note that smaller wavelength waves have higher frequencies, and higher amounts of energy.[/b] [img style='width:100vw' src='https://res.cloudinary.com/deylrqt2d/image/upload/v1488037941/SL_EMspectrum_bqazem.jpg'] [u]Properties of All EM Waves:[/u] [ul] [li]They all transfer from one place to another[/li] [li]They are all transverse waves[/li] [li]They can all be refracted/reflected/diffracted[/li] [li]They can all travel through a vacuum at 300,000,000m/s[/li] [li]Wavespeed = Frequency [multiply] Wavelength[/li] [li]The shorter the wavelength (the higher the frequency), the more dangerous the wave[/li] [/ul] [b]Gamma Rays:[/b] Very short wavelength, and is produced by the decay of radioactive substances, and can be used to do many things (such as kill cancer cells), but must be used carefully. [b]X-Rays:[/b] Similar to Gamma Rays, and doctors use X-Rays to check bones and teeth. [b]UV-Rays:[/b] Hot Objects produce UV rays. In small amounts, it produces Vitamin D, in Humans, and in large amounts - Skin Cancer. Darker skin protects you from UV rays. Luckily, most UV radiation is absorbed by the Ozone layer. Some chemicals [b]fluoresce[/b], under UV rays, and produce visible light. [b]Visible Light:[/b] It is the only part of the EM spectrum that we can perceive with our eyes. We are most sensitive to green/yellow light. [b]Infrared Radiation:[/b] Given out by warm objects, and can be used to detect living creatures. Every object with a temperature greater than absolute zero (0 Kelvin), emits this form of radiation. [b]Thermographs[/b] utilize this. [b]Radio Waves and Microwaves:[/b] These have the longest wavelengths, and have several kinds: [ul] [li][b]Microwaves[/b] - the shortest one in this category - can be used for communication and radar (diagram later on).[/li] [li][b]UHF[/b] - [b]Ultra High Frequency[/b] - used to transmit TV programmes.[/li] [li][b]VHF[/b] - [b]Very High Frequency[/b] - used to transmit radio programmes and police/ambulance messages.[/li] [li][b]Medium and Long Waves[/b] are used to transmit over long distances. They diffract along the curve of the earth, and around objects, to relay information.[/li] [/ul] [img src='https://res.cloudinary.com/deylrqt2d/image/upload/v1488044662/radar_communication_gcp5ny.svg'] The blue lines are the transmitted waves, from the radar, and then they return from the aircraft (red lines), and with responding data. [h3]Visible Spectrum[/h3] [img style='width:100vw' src='https://res.cloudinary.com/deylrqt2d/image/upload/v1488045268/visible-a_ek3srl.png'] The wavelength longer than red is [b]Infrared[/b]. The wavelength shorter than Violet is [b]Ultraviolet[/b].