The electromagnetic spectrum mgmbtc

Basic Biomedical Equipment Servicing Level II Page 1 of 26

The Electromagnetic Spectrum

Prepared by : Rafael P. Iwayan

Page 2 of 26 Prepared by : Rafael P. IwayanBasic Biomedical Equipment Servicing Level II

Electromagnetic Spectrum—name for the range of electromagnetic waves when placed in order of increasing frequency

Page 3 of 26Basic Biomedical Equipment Servicing Level II Prepared by : Rafael P. Iwayan

What is it?

• The electromagnetic spectrum is the complete spectrum or continuum of light including radio waves, infrared, visible light, ultraviolet light, X-rays and gamma rays

• An electromagnetic wave consists of electric and magnetic fields which vibrates thus making waves.


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Waves

• Properties of waves include speed, frequency and wavelength

• Speed (s), frequency (f) and wavelength () are related in the formula s = f x

• All light travels at a speed of 3 x 108 m/s in a vacuum


• At this speed they can go around the world 8 times in one second.

• Electromagnetic waves travel VERY FAST – around 300,000

kilometres per second (the speed of light).


Wavelength, Frequency and Energy

• Since all light travels at the same speed, wavelength and frequency have an indirect relationship.

• Light with a short wavelength will have a high frequency and light with a long wavelength will have a low frequency.

• Light with short wavelengths has high energy and long wavelength has low energy


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Wavelength

Basic Biomedical Equipment Servicing Level II Prepared by : Rafael P. Iwayan

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Frequency vs. Wavelength


Radio waves

• Low energy waves with long wavelengths• Includes FM, AM, radar and TV waves• Wavelengths of 10-1m and longer• Low frequency • Used in many devices such as remote control

items, cell phones, wireless devices, etc.


Microwaves• Longer than radio, shorter

than light and infrared• Wavelength 1 x 10 - 4 m to

1 x 10-1 m • First used in radar, now

used in communication, medicine and consumer use (microwave ovens)


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Radio waves vs. Microwaves


Infrared waves

• Invisible electromagnetic waves that are detected as heat

• Can be detected with special devices such as night goggles

• Used in heat lamps• Higher energy than microwaves

but lower than visible light


Visible Light

• The portion of the electromagnetic spectrum that human eyes can detect

• ROY G BIV (red, orange, yellow, green, blue, indigo, violet)

• Red is the lowest frequency and violet is the highest frequency


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Ultraviolet waves

• Higher energy than light waves• Can cause skin cancer and blindness in

humans• Used in tanning beds and sterilizing

equipment


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Ultraviolet waves vs. Visible Light vs. Infrared waves


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Ultraviolet waves vs. Visible Light vs. Infrared waves


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Electromagnetic Radiation


X-Rays

• High energy waves• First discovered by

Roentgen • Used in medicine,

industry and astronomy• Can cause cancer


Gamma rays

• Highest energy• Blocked from Earth’s surface

by atmosphere• Gamma knife is a device

used to treat brain tumors with a high dose of radiation therapy in one day.



Time to think…..

• 1. What is the relationship between frequency and wavelength?

• 2. What is meant by ‘spectrum’?

• 3. What does ROY G BIV mean?


Now, let’s really think

• 4. Can you actually see x-rays?– Support your answer.

• 5. Which color is more energetic, red or yellow?

• 6. Which type of wave travels faster, gamma or radio?

• 7. Why are microwaves more dangerous than radio waves?



• Brief SUMMARY• A. All electromagnetic waves travel at the

same speed. (300,000,000 meters/second) in a vacuum.

• B. They all have different wavelengths and different frequencies.– Long wavelength-lowest frequency– Short wavelength highest frequency– The higher the frequency the higher the

energy.

Answers• 1. Frequency and wavelength are properties of waves and since

speed is constant for em waves, as frequency increases, wavelength decreases.

• 2. Spectrum is a continuum of all electromagnetic waves• 3, ROY G BIV is the difference colors of the visible light in order of

longest wavelength to shortest wavelength.• 4. X-rays can not be seen, only the waves in the visible light portion

are visible.• 5. Yellow is higher energy than red because it has a shorter

wavelength and higher frequency.• 6. Both travel at the same speed, 300,000 km/s (all em waves travel

at the same speed)• 7. Microwaves have a higher frequency than radio and carry more

energy.


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Thank you!


Education

The electromagnetic spectrum mgmbtc