MAP TAP 2003-2004The Electromagnetic Spectrum1 Wavelength/frequency/energy.

The Electromagnetic Spectrum 1MAP TAP 2003-2004

The Electromagnetic Spectrum

Wavelength/frequency/energy


Teacher Page

• Content: Physical Science—The Electromagnetic Spectrum

• Grade Level: High School• Creator: Dorothy Walk• Curriculum Objectives: SC 1; Intro

Phys/Chem IV.A (waves)


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.


Waves

• Properties of waves include speed, frequency and wavelength

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

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


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


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)


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


Ultraviolet waves

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

humans• Used in tanning beds and sterilizing

equipment


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


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?


Think about it….

• You have just been involved in a traffic incident that leaves you stranded on the side of the road. Which part of the electromagnetic spectrum would be of the most use to you and why?


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.

MAP TAP 2003-2004The Electromagnetic Spectrum1 Wavelength/frequency/energy.

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Transcript of MAP TAP 2003-2004The Electromagnetic Spectrum1 Wavelength/frequency/energy.