Final Ppt Updated on 21-02-11

8/6/2019 Final Ppt Updated on 21-02-11

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Electromagnetic Spectrum


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PRESENTED BY:- SHOHAIM SHAIKH


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THE ELECTROMAGNETIC SPECTRUM

Electromagnetic Spectrum The electromagneticspectrum is the range of all possible frequencies of

electromagnetic radiation

Electromagnetic Waves signals that oscillate

Produced by the movement of electrically charged

particles


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Can travel in a vacuum (t

hey do NO

Tneed a medium)

Travel at the speed of light

Frequency The number of complete waves passingthrough any fix point in one second

- cycles per second (cps)

- Hertz


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THE ELECTROMAGNETIC SPECTRUMWavelength The distance between a point on one

electromagnetic wave and exactly the same point on the

next wave


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THE ELECTROMAGNETIC SPECTRUM


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RADIO WAVES

Longest wavelength EM waves Ranges from 0.1m - 100km

Frequency < 3 x 109Hz

Energy < 2 x 10-24J

Uses:

TV broadcasting

AM and FM broadcast radio

Avalanche beacons

Heart rate monitors

Cell phone communication


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The use of concentrated radio waves appears to be

a safe andeffective way to "burn" away abnormal

cell growthin theesophagus that can be a

precursor of cancer

An MRI scan is a radiology technique that uses

magnetism, radio waves, and a computer to

produceimages of body structures


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MICROWAVES W

avelength

s from 1 mm- 0.1 m Frequency 3 x 109 - 3 x 1011Hz

Energy 2 x 10-24- 2 x 10-22J

Uses

Microwaves use in heating Microwave ovens

Bluetoothheadsets

Broadband Wireless Internet

Radar

GPS


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Micro-wave diathermy waves used for treatment is ofWave

length - 12.25 cmFrequency - 2,450 cycles/sec

Production of Waves

The waves are obtained by heating special type of valve called

Magnetron. The output is carried to a small aerial and

microwaves are emitted.

Where useful?

Pain

Bacterial infection

Septic fingers

Boils

Abscess


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Where it should not be used?

Cancer

Tuberculosis of Bone Recent exposure to X-rays

Defective blood circulation (In cases like Diabetes)

Advantages Pain is relieved

Healing of infections is faster

Aids in relaxation

Disadvantages

Burns

Injuries to eyes


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INFRARED RADIATION

Wavelengths in between microwaves and visible light

Ranges from400nm -0.4mm

Frequency 3 x 1011 - 4 x 1014Hz

Energy 2 x 10

-22

- 3 x 10-19J

Uses:

Night vision goggles

Remote controls

Pulse oximetryHeat-seeking missiles


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Infra-red rays are electromagnetic waves, the heat energy

obtained from the rays are used to relieve pain.

Infra-red Rays Generators (2 types)

Non-Luminous Generator

Luminous Generator

Where useful?

Pain

Muscle strain

Where it should not be used?

Defective Blood Supply to the area (eg. In case of diabetes)

Any Blood loss

Defective skin sensation (nerve damage)


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INFRARED: PULSE OXIMETRY

Heart rate:81 bpm

Blood oxygenation: 99%


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VISIBLE LIGHT

Only type of EM wave able to be detected by the humaneye

Wavelength ranges from 400nm-750nm

Frequency 4 x 1014 - 7.5 x 1014Hz

Energy 3 x 10-19 - 5 x 10-19 J

Violet is the highest frequency light

Red light is the lowest frequency light


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Visible light radiation usein endoscopy


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ULTRAVIOLET

Shorter wavelengths than visible light

Ranges from 10nm- 400nm

Frequency 7.5 x 1014 - 3 x 1016Hz

Energy 5 x 10

-19

- 2 x 10-17J

Uses:

Sterilizing medical equipment

Water disinfection

Security images on moneyBlack lights


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Various skin condition

F

ormation ofVitamin D in the skin

They are divided into three categories:UV-A, UV-B, and UV-C

UV-Ahas the longest wavelength and is least dangerous; UV-B is

of intermediate wavelength and is the type of sun emission thatcauses sunburn and, over long periods of exposure, skin cancer;

UV-Chas a very short wavelength and kills bacteria and viruses so

well that it is often used to sterilize surfaces

Adverseeffect Tan

Sun Burn

Snow Blindness


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X-RAYS Tiny wavelength ranges from 0.01pm 100 nm

Frequency 3 x 1016 - 3 x 1019Hz

Energy waves 2 x 10-17 - 2 x 10-14 J

Uses:

Medical imaging

Airport security

Inspecting industrial welds


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X-RAYS: RADIOTHERAPY

X-rays or other radiation can damage theDNA in cells and kill them

This is why radiation can be dangerous

But cells which are dividing rapidly are morelikely to be killed

So we use x-rays to kill t

he rapidly-dividingcancer cells

We must still ensure that healthy tissue isundamaged


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GAMMA RAYS Smallest wavelengths, highest energy EM waves

Wavelength 3 x 1019Hz

Energy ranges > 2 x 10-14 J

Uses

Food irradiation

Treating wood flooring


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Cancer treatment

Intracoronary gamma radiation is a feasible, safe, andeffective tool in the treatment of diffuse in-stent

restenosis.


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Final Ppt Updated on 21-02-11

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