Electromagnetic Spectrum: Wavelength, frequency and energy

Electromagnetic Spectrum: Wavelength, frequency and energy www.assignmentpoint.com

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) www.assignmentpoint.com

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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. www.assignmentpoint.com

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 www.assignmentpoint.com

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 www.assignmentpoint.com

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. www.assignmentpoint.com

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) www.assignmentpoint.com

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 Infrared waves www.assignmentpoint.com

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 www.assignmentpoint.com

Ultraviolet waves • Higher energy than light waves • Can cause skin cancer and blindness in humans • Used in tanning beds and sterilizing equipment www.assignmentpoint.com

X-Rays • High energy waves • First discovered by Roentgen • Used in medicine, industry and astronomy • Can cause cancer www.assignmentpoint.com

Gamma rays • Highest energy • Blocked from Earth’s surface by atmosphere www.assignmentpoint.com

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? www.assignmentpoint.com

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? www.assignmentpoint.com

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? www.assignmentpoint.com

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. www.assignmentpoint.com

Electromagnetic Spectrum: Wavelength, frequency and energy