ELECTROMAGNETIC SPECTRUM

ELECTROMAGNETIC SPECTRUMPresentation Made By:-Shalini Singh TaknetELECTROMAGNETIC SPECTRUM

Address people1

Entire Spectrum of EM WavesThe spectrum is arranged from long to short wavelength or from low to high frequency.The speed of all EM waves is the same!

Explain previously discussed slide with the help of this image2

What is an Electromagnetic Wave? Electromagnetic waves are produced by rapidly accelerated or decelerated charged particles Consist of oscillating electric and magnetic fields that are at right angles to each other They travels in vacuum of space in the form of sinusoidal waves with the speed of light: 3.0x108m/s

It contains properties of both electrical and magnetic waves.

Now turn the topic from electromagnetic spectrum to its cause or you may to its origin i.e. e.-wave3

Electromagnetic Waves

EM waves transport energy through empty space, stored in propagating electric and magnetic fields.Magnetic field variation is perpendicular to magnetic field.

A single freq. electromagnetic wave exhibits a sinusoidal variation of electric and magnetic fields in space.

Explain a little about e.-wave4

Wavelength and Frequency

Like an ocean wave, em wave also have crest and trough5

Energy Content of EM WavesThe energy carried by anEM wave is determined byThe frequency of the wave

E = h fE = energyh = constant known as Plancks constantf = frequency

Dangerous EM waves have very high frequencies and should be avoided

Explain previously shown diagram6

Electromagnetic SpectrumThe entire range of EM waves is known as the Electromagnetic Spectrum.Radio wavesMicrowavesInfrared wavesVisible lightRedOrange YellowGreenBlue IndigoVioletUltravioletX-raysGamma Rays

Discuss now the introduction part of e-wave7

Radio WavesLow frequency and longer wavelength waves.

Radio stations transmit information into coded form.

RADIO WAVES

Start with intro part of first wave of spec.8

The Electromagnetic Spectrum

Discuss first wave preceding with a little intro of e-spec. 9

AM Radio Waves

AM-amplitude modulation is a process of radio broadcasting.

Ionosphere is much effective.

Radio antenna use for pick up radio signals at a time.

Short Waves

Shortwave radios can be used communication service .

Shortwave radio is used for broadcasting of voice and music for long distance. Short waves used in transceiver to send and receive Morse code messages from all over the United States.

Television WavesTelevision waves are also carried by radio waves.

Most TV stations broadcast radio waves that have shorter wavelengths and higher frequencies.

Some waves carrying TV signals are transmitted to satellites around the Earth.

MicrowavesMicrowaves is a subset of radio waves .

They have wavelengths ranging from as long as 1m to as short as 1mm and frequencies in the range of 1GHz to 300GHz

Take the topic to the other part of EM waves i.e. MICROWAVES13

MicrowavesToday many artificial sources of microwavesare available for use like CMBR, Maser etc.other then the mainand natural source viz. sun.

Over exposure of Microwaves may have carcinogenic effect. It includes serious burns and can produce cataracts.

14

Applications of MicrowavesThese waves are used in communication

Most radio astronomy uses microwaves.

It is also used in navigation.

Also used in microwave oven to cook food.

Application of MicrowavesRadar (radio detection and ranging)- microwaves used to detect the speed and location of an object.

Radar uses microwave to detect the range, speed and other characteristics of remote objects

Infrared WavesShorter wavelength and higher frequencies.

Infrared waves are emitted by the sun and objects that emit heat. The higher the temperature the more the infrared radiation.

The Infrared light is emittedor absorbed by moleculeswhen they change their rotational and vibrationalmovements

Explain about infrared rays.17

Applications Of Infrared WavesInfrared Waves are used in Night Vision equipments when there is no much light to see.

Infrared Radiations are also used in tracking- known as infrared homing .

Infrared rays data transmission is also employed in short range communication among computer peripherals

Infrared radiation can be used as a deliberate heating source.

Infrared Waves Images of human being taken by thermal camera, radiating infrared waves

Image of our globe showing temperature all over the Earth

The light we see with our eyes is really a very small portion of the EM spectrum.

A RAINBOW shows the Optical part of the EMspectrum; Infrared would be located just beyond the red side of the rainbow with ultraviolet appearing just beyond the violet end.Visible Rays

Explain about visible rays and its application20

Visible LightLongest wavelength is red.Shortest wavelength is violet.Colors oflightis the visiblespectrum.

This Part of spectrum is similar torainbows orwhite lightspectrum produced by prism.

Explanation of visible rays technical part.21

Visible Rays

Ultraviolet Rays

The wavelength of UV rays have higher energy and is shorter than the violet end of the visible spectrum.

Some insects can see ultraviolet light . Sun emits a extensive . amount of UV waves. .

Debate on UV rays24

Ultraviolet LightThey are too energetic that they can break chemical bonds making molecules unusually reactive or ionizing.The disruptive effects of UV radiation on skin cells can cause Sunburn, or Skin cancer.It can irreparably damage the complex DNA molecules in the cells. The sun emits a large amount of UV radiation, which could potentially turn Earth into a barren desert.

Ultraviolet waves are of 3 types.[NUV,EUV,FUV]

NUVFUVFUVEUVEUVFUVNUV

Explain UV with diagram.25

X-Rays and Gamma RaysIn Spectrum both rays are mostly shown together as the electromagnetic radiation emitted by X-ray tubes almost invariably had a longer wavelength than the radiation emitted by radioactive nuclei (gamma rays).The distinction between X-rays and gamma rays has changed in recent decades only

X-Rays and Gamma RaysThe gamma ray photon is identical to an x-ray, since both are electromagnetic rays.

The terms x-ray and gamma rays are statements about origin rather than implying different kinds of radiation.

Gamma rays, X-rays, visible light, and radio waves are all forms of electromagnetic radiation.

The only difference is the frequency and hence the energy of the photons.

X-RaysThey are shorter in wavelength than UV rays and longer than gamma rays.

The discoverer of X-Rays, Wilhelm Conrad Rntgen had named it X-radiation to signify an unknown type of radiation.

X-rays carry great deal of energy and can travel through a variety of materials. In universe,X-rays are emitted by pulsars, black holes supernovas

Application of X-RaysX-rays are used to examine soft tissues by CAT or CT scanning.

X-rays are useful in the detection of pathology of the skeletal system X-rays are used as a treatment is known as radiation therapy.

Application of X-RaysX-ray microscopic analysis is used to produce images of very small objects.Industrial radiography uses X-rays for inspection of industrial parts, particularly welds.For security, scanners use X-rays for inspecting the interior of luggage etc.

X-rays are also used for Fine Art Photography

X-RayThe part to be X-rayed is placed betweenthe X-ray source and the image receptorto produce a shadow of the internal structure . X-rays are partially attenuated by dense tissues and pass more easily throughsoft tissues.

Areas where the X-rays strike darken when developed, causing denser tissues to appear lighter than the surrounding soft tissue

Gamma RaysThe term gamma ray is used to denote electromagnetic radiation from the nucleus as a part of a radioactive process.

The energy of nuclear radiation is extremely high Shorter wavelength and higher frequencies of all EM waves.

Gamma RaysToo Much exposure of Gamma Rays can kill cells

Gamma rays are the main reason for mutations.In interactions with matter, gamma rays are ionizing radiation and produce physiological effects.

Gamma Rays The Moon as seen by the Compton Gamma Ray Observatory, in gamma rays of greater than 20 MeV.

Image of entire sky in 100 MeV or greater gamma rays

A hypernova. Artist's illustration showing the life of a massive star as nuclear fusion converts lighter elements into heavier ones

Application of Gamma Rays Gamma Rays are used to estimate the extragalactic background light in the universe.

Gamma radiation is often used to kill living organisms, in a process called irradiation.Gamma rays are also used to treat some types of cancer

Application of Gamma Rays Gamma-induced molecular changes can also be used to alter the properties of semi-precious stones, and is often used to change white topaz into blue topaz.Gamma rays detectors like VACIS are used to screen merchant ship containers, and other loading vehicles like Truck.

Gamma rays are also used for diagnostic purposes in nuclear medicine in imaging techniques.

Thank You