G10 Science Q2 Module 2 Uses of Electromagnetic Waves PDF

The Electromagnetic Spectrum The Electromagnetic Spectrum 1 S10FE - IIc - d - 48 Cite examples of practical applications of the different regions of EM waves, such as the use of radio waves in telecommunications 2 What is the Electromagnetic Spectrum?...

The Electromagnetic Spectrum The Electromagnetic Spectrum 1 S10FE - IIc - d - 48 Cite examples of practical applications of the different regions of EM waves, such as the use of radio waves in telecommunications 2 What is the Electromagnetic Spectrum? ► The electromagnetic spectrum is the complete spectrum (or continuum) of all forms of “light” ► An electromagnetic wave consists of electric and magnetic fields which vibrate - thus making waves. 3 ► Vibrations  What is the Electromagnetic Spectrum? ► The electromagnetic 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 Spectrum 4 The Electromagnetic Spectrum 5 Waves ► Properties of electromagnetic waves include speed, frequency and wavelength ► Speed (s), frequency (f) and wavelength (λ) are related in the formula: ►s = f x λ ► All light waves travel at a speed of 3 x 108 m/s in a vacuum The Electromagnetic Spectrum 6  Relationship Between Wavelength & Frequency ⦿ All parts of the electromagnetic spectrum travel at the same speed ⦿ Therefore, wavelength and frequency have an indirect relationship. ⦿ This means that as one characteristic increases, the other decreases ⦿ In other words, as wavelength increases, frequency decreases The Electromagnetic Spectrum 7  Relationship Between Wavelength & Frequency ► As wavelength decreases, frequency will? ► increase ► See the relationship The Electromagnetic Spectrum 8 Wavelength, Frequency, Energy ► 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 The Electromagnetic Spectrum 9 Wavelength, Frequency, Energy Fill in the table below: wavelength frequency energy long high The Electromagnetic Spectrum 10  Wavelength & Energy smaller wavelengths increasing frequency 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, The Electromagnetic Spectrum 11 etc) exist. The Electromagnetic Spectrum 12  Radio waves ► 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. The Electromagnetic Spectrum 13 Microwaves ⦿ 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) The Electromagnetic Spectrum 14  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 The Electromagnetic Spectrum 15 Visible Light ► The portion of the electromagnetic 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 The Electromagnetic Spectrum 16 The Electromagnetic Spectrum 17 Ultraviolet waves ► Higher energy than light waves ► Can cause skin cancer and blindness in humans ► Used in tanning beds and sterilizing equipment The Electromagnetic Spectrum 18 X-Rays ► High energy waves ► Used in medicine, industry and astronomy ► Can cause cancer The Electromagnetic Spectrum 19 Gamma rays ► Highest energy ► Blocked from Earth’s surface by atmosphere The Electromagnetic Spectrum 20 The Electromagnetic Spectrum 21 22