 # Aim: How can we explain the Electromagnetic Spectrum?

## Presentation on theme: "Aim: How can we explain the Electromagnetic Spectrum?"— Presentation transcript:

Aim: How can we explain the Electromagnetic Spectrum?
Do Now: A light wave in a vacuum is traveling with a frequency of 6.2 x 1010 Hz. What is the wavelength? v = fλ 3.0 x 108 m/s = (6.2 x 1010 Hz)λ λ = 4.8 x 10-3 m

The Electromagnetic Spectrum
The speed of all waves of the EM spectrum in a vacuum is the speed of light (c). = 3.00 x 108 m/s

What type of wave has the longest wavelength? What type of wave has the shortest wavelength? Long Radio Waves Gamma Rays

About what is the wavelength of visible light?
10-7 m

What type of wave has the highest frequency? What type of wave has the lowest frequency? Gamma Rays Long Radio Waves

Visible light only makes up about 2% of the EM spectrum!

What color light has a frequency between 6. 10 x 1014 Hz and 5
What color light has a frequency between 6.10 x 1014 Hz and 5.20 x 1014 Hz? What color light has a frequency between 5.03 x 1014 Hz and 4.82 x 1014 Hz? GREEN ORANGE

In a vacuum, a monochromatic beam of light has a frequency of 6
In a vacuum, a monochromatic beam of light has a frequency of 6.3 x 1014 Hz. What color is the light? BLUE

Finding Frequency or Wavelength of an Electromagnetic Wave
Use the equation v = fλ Just remember that any EM wave has a velocity of…. 3.00 x 108 m/s Hence, c = fλ

Determine the color of a ray of light with a wavelength of 6
Determine the color of a ray of light with a wavelength of 6.21 x 10-7 m. c = fλ (3.00 x 108 m/s) = f(6.21 x 10-7 m) f = 4.83 x 1014 Hz (ORANGE)

When asked to refer to a specific color’s frequency, choose the value to the LEFT of that color!

What is the wavelength of red light?
c = fλ 3 x 108 m/s = (4.82 x 1014 Hz) λ λ = 6.2 x 10-7 m

Calculate the wavelength of WPLJ (95.5 fm)
c = fλ Hint: fm radio transmits in megahertz (3.00 x 108 m/s) = (95.5 x 106 Hz) λ λ = 3.14 m

In a vacuum, all electromagnetic waves have the same
Wavelength Frequency Speed amplitude

A 2. 00 x 106 Hz radio signal is sent a distance of 7
A 2.00 x 106 Hz radio signal is sent a distance of 7.30 x 1010 meters from Earth to a spaceship orbiting Mars. Approximately how much time does it take the radio signal to travel from Earth to the spaceship? 4.11 x 10-3 s 2.43 x 102 s 2.19 x 108 s 1.46 x 1017 s

How long does it take light to travel from the Sun to the Earth?