The Electromagnetic Spectrumpehs.psd202.org/documents/aseverin/1536609431.pdf · The EM spectrum...

transcript

1The Electromagnetic Spectrum

EM spectrum is complete spectrum of all

forms of “light”

EM wave consists of

electric fields which vibrate

magnetic fields making waves.

The EM spectrum consists of:

radio waves

cell phone waves

microwaves

radar waves

infrared waves

visible light waves

ultraviolet waves

x-ray waves

gamma waves

The Electromagnetic Spectrum3

Properties of EM waves include speed, frequency, wavelength

Speed (c), frequency (f) and wavelength (λ) are related in the formula:

c = f x λ

All light waves travel at speed of 3 x 108 m/s in a vacuum

All parts of EM spectrum travel at same speed.

λ and f have indirect relationship.

As one the other

As λ , f

As wavelength decreases, frequency does what?

increases

Electromagnetic wave characteristics:• short wavelengths have a high frequency

• long wavelengths have a low frequency

Electromagnetic waves & Energy:• high frequency waves have high energy

• low frequency waves have low energy

increasing frequency and increasing energy

If you haven’t already, sketch this drawing into

your notes. Don’t worry so much about the actual

wavelengths, just get the general shape and where

the various forms of light (radio, infrared, x-ray,

etc) exist.

smaller wavelengths have

Low energy waves with longest wavelengths

Includes FM, AM, radar and TV waves

Wavelengths of 1 m (10 -1 m) and longer

Low frequency

Used in many devices such as remote control

items, cell phones, wireless devices, etc.

Only radio waves are longer

Wavelength 1 x 10-1 m to 1 x 10 - 4 m (1 m to 0.001 m)

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

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

The portion of the EM spectrum that human

eyes can detect.

ROY G BIV (red, orange, yellow, green, blue,

indigo, violet)

Which color has the lowest frequency? red has the lowest frequency – violet the highest

Higher energy than light waves

Can cause skin cancer and blindness in

humans

Used in tanning beds and sterilizing

equipment

High energy waves

Used in medicine,

industry and

astronomy

Can cause cancer

Highest energy

Blocked from

Earth’s surface

by atmosphere

1. What is the relationship between

frequency and wavelength?

2. What characteristic of gamma

waves gives them their high

energy?

3. What does ROY G BIV mean?

What part of the electromagnetic

spectrum does it refer to?

4. Which color is more energetic,

red or yellow?

5. Which type of wave travels faster,

gamma or radio?

6. Why are microwaves more

dangerous than radio waves?

7. 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

1. Frequency and wavelength are properties of waves and since speed is constant for em waves, as frequency increases, wavelength decreases. In other words, they have an indirect relationship.

2. Gamma waves get their high energy from their extremely short wavelengths (or extremely fast frequency)

3. ROY G BIV stands for “red, orange, yellow, green, blue, indigo, and violet. They are the colors of the visible light in order of longest wavelength to shortest wavelength.

4. Yellow is more energetic than red because it has a shorter wavelength (or larger frequency)

5. Gamma waves and radio waves travel at the same speed

6. Microwaves are more dangerous than radio waves because they have a higher frequency and carry more energy.

The Electromagnetic Spectrumpehs.psd202.org/documents/aseverin/1536609431.pdf · The EM spectrum...

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