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ELECTROMAGNETIC RADIATION

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Balasubramani Sriram

on 10 January 2016

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Transcript of ELECTROMAGNETIC RADIATION

Infrared
Infrared (IR) light is electromagnetic radiation with longer wavelengths than those of visible light, extending from the nominal red edge of the visible spectrum at 700 nanometers (nm) to 1 mm. This range of wavelengths corresponds to a frequency range of approximately 430 THz down to 300 GHz. Most of the thermal radiation emitted by objects near room temperature is infrared. It was discovered by British astronomer Willam Hershel.
VISIBLE LIGHT
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 700 nm. In terms of frequency, this corresponds to a band in the vicinity of 430–790 THz.
Uses

seeing things
used in optical fibres
endoscopy blue light treatment for jaundice
used in Compact Disc & DVD players, where the light is reflected from the tiny pits in the disc, and the pattern is detected and translated into sound or data.
in aircraft weapon aiming systems.
Dangers

very bright light can damage eyes.
Microwaves

Microwaves are a form of electromagnetic radiation with wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz (0.3 GHz) and 300 GHz. It indicates that microwaves are "small" compared to waves used in typical radio broadcasting, in that they have shorter wavelengths. In a mobile phone, they're made by a transmitter chip and an antenna, in a microwave oven they're made by a "magnetron".

Their wavelength is usually a couple of centimetres. Stars also give off microwaves.
Uses of Mircowaves
Microwaves cause water and fat molecules to vibrate, which makes the substances hot. So we can use microwaves to cook many types of food.
Mobile phones use microwaves, as they can be generated by a small antenna, which means that the phone doesn't need to be very big.
Microwaves are also used by fixed traffic speed cameras, and for radar, which is used by aircraft, ships and weather forcasters.
GPS
Dangers of microwaves
Prolonged exposure to microwaves is known to cause "cataracts" in your eyes, which is a clouding of the lens, preventing you from seeing clearly.
microwaves from mobile phones can affect parts of your brain
modern radar military planes can cook you with the intense microwaves it uses
water absorbs microwaves so if living cells are exposed the water can boil bursting and killing cells.
Dangers of Infrared
The danger to people from too much Infra-Red radiation is very simple - burns and overheating.
Dangers
Exposure to gamma rays is extremely dangerous as they kill body cells or interfere with one's DNA functions and interpretations. This could to lead to very serious medical conditions such as body cancers and deformities.
They cause mutations in growing tissues, so unborn babies are especially vulnerable.
ELECTROMAGNETIC RADIATION
X-rays uses

X-RAY DANGERS
Highly ionizing which can damage living tissues.
Causes cancer
genetic mutations in sperm and eggs leading to dangerous health problems in offspring.
X RAYS

X-radiation is a form of electromagnetic radiation. Most X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 100 eV to 100 keV.
Ultraviolet Rays
Ultraviolet rays are rays with the wavelength shorter than visible light but longer than X-rays (in the range between 400 nm and 10 nm.) . It is so named because they have frequencies higher than violet light. A large fraction of UV, including all that reaches the surface of the Earth, is classified as non-ionizing radiation.
Uses of UV light
Dangers of UV
Aging
Immmune system damage and eye damage
Skin cancer
Introduction
It is the flow of energy at the universal speed of light through free space or through a material medium. In the form of electric and magnetic fields that make up electromagnetic waves. In such a wave, time-varying electric and magnetic fields are mutually linked with each other at right angles and perpendicular to the direction of motion. An electromagnetic wave is characterized by its wavelength and the frequency.
THEY ARE TRANSVERSE WAVES
TRAVEL AT SPEED OF LIGHT IN VACUUM
CAN BE POLARIZED
CAN BE REFLECTED AND REFRACTED.
CAN BE DIFFRACTED
CARRY NO ELECTRIC CHARGE
CAN BE ABSORBED AND EMITTED BY MATTER.
DO NOT NEED A MATTER TO TRAVEL EG: AIR.
Some facts
Radio waves

Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies from 300 GHz to as low as 3 kHz, and corresponding wavelengths ranging from 1 millimeter (0.039 in) to 100 kilometers (62 mi). Like all other electromagnetic waves, they travel at the speed of light. Naturally occurring radio waves are made by lightning, or by astronomical objects.
Uses

inspection of Bones
Radio therapy
killing cancer cells
CT scan
Sterilization of medical equipment.
AM and FM broadcast radio
Heart rate monitors
Dangers

Large doses of radio waves are believed to cause cancer, leukemia and other disorders.
They also lead to extreme large temperature rise which in the long term is disastrous.
Gamma rays
Uses
Gamma radiation is often used to kill living organisms, in a process called irradiation.
sterilizing medical equipment (as an alternative to autoclaves or chemical means)
removing decay-causing bacteria from many foods or preventing fruit and vegetables from sprouting to maintain freshness and flavor.
Dangers
Exposure to gamma rays is extremely dangerous as they kill body cells or interfere with one's DNA functions and interpretations. This could to lead to very serious medical conditions such as body cancers and deformities.
They cause mutations in growing tissues, so unborn babies are especially vulnerable.
Dangers of Gamma Rays
Exposure to gamma rays is extremely dangerous as they kill body cells or interfere with one's DNA functions and interpretations. This could to lead to very serious medical conditions such as body cancers and deformities.
They cause mutations in growing tissues, so unborn babies are especially vulnerable.
Gamma radiation, also known as gamma rays, refers to electromagnetic radiation of extremely high frequency and therefore high energy per photon. Gamma rays are ionizing radiation, and are thus biologically hazardous. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900, while studying radiation emitted from radium. Villard's radiation was named "gamma rays" by Ernest Rutherford in 1903.
Uses of Infrared Radiation
Night vision
data transmission
infra-red radiation can be used to remotely determine the temperature of objects
Missiles often use infra-red tracking, also known as infra-red homing
Fluoroscence and lighting
Vitamn D
Curing
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