Light and Optics Intro

Section 1: Intro to Electromagnetic Waves Intro Questions: What is the difference between mechanical and electromagnetic waves? Name as many types of electromagnetic waves you can What is the speed of light and any other electromagnetic wave in space?

The Electromagnetic Wave Characteristics: Require no medium Transverse waves of oscillating electromagnetic fields Transverse waves move perpendicular to the direction the wave moves The electric and magnetic fields are at right angles to each other All electromagnetic waves travel at 3.0 x 108 m/s Electric Field Direction of travel towards you Magnetic Field

3.0 x 108 = λ • f V = λ • f The Electromagnetic Spectrum Wavelength Decreases Frequency Increases Energy Increases 3.0 x 108 = λ • f V = λ • f More Penetration and Dangerous Velocity = 3.0 x 108 m/s For All Electromagnetic Waves

Section 2: Electromagnetic Wave Math V = λ • f Speed of light distance-time calculations Velocity = 3.0 x 108 m/s for all electromagnetic waves If you see any of these you have an electromagnetic wave and v = 3.0 x 108 m/s Radio Waves, Microwaves, Infrared, Visible Light, Ultra Violet, X-rays, Gamma Rays

Example 1 The AM radio band extends from 5.4 x 105 Hz to 1.7 x 106 Hz. What are the longest and shortest wavelengths in this frequency range?

Example 1 The AM radio band extends from 5.4 x 105 Hz to 1.7 x 106 Hz. What are the longest and shortest wavelengths in this frequency range?

Example 2 What is the frequency of an electromagnetic wave if it has a wavelength of 1.0 km?

Example 2 What is the frequency of an electromagnetic wave if it has a wavelength of 1.0 km?

Example 3 How long does it take for light from the sun to reach Earth if the sun is 1.5 x 1011 m away?

Example 3 How long does it take for light from the sun to reach Earth if the sun is 1.5 x 1011 m away?

Radio waves Longest wavelength EM waves, low frequency, low energy Uses: TV broadcasting AM and FM broadcast radio Avalanche beacons Heart rate monitors Cell phone communication Click the little rainbow box in the top right corner to return to the overview EM spectrum diagram

Microwaves Wavelengths from 1 mm- 1 m Uses: Microwave ovens Bluetooth headsets Broadband Wireless Internet Radar GPS Click the little rainbow box in the top right corner to return to the overview EM spectrum diagram

Infrared Radiation Wavelengths in between microwaves and visible light Uses: Night vision goggles Remote controls Heat-seeking missiles Heat lamps Click the little rainbow box in the top right corner to return to the overview EM spectrum diagram

Visible light Only type of EM wave able to be detected by the human eye Violet is the highest frequency light Red light is the lowest frequency light ROYGBIV Click the little rainbow box in the top right corner to return to the overview EM spectrum diagram

Ultraviolet Shorter wavelengths than visible light Uses: Black lights Sterilizing medical equipment Water disinfection Security images on money There is one more UV slide…

X-rays Tiny wavelength, high energy waves Uses: Medical imaging Airport security Inspecting industrial welds Click the little rainbow box in the top right corner to return to the overview EM spectrum diagram

Gamma Rays Smallest wavelengths, highest energy EM waves Uses Food irradiation Cancer treatment Treating wood flooring Click the little rainbow box in the top right corner to return to the overview EM spectrum diagram