Electromagnetic Waves & the Electromagnetic Spectrum

Transcription

1 Electromagnetic Waves & the Electromagnetic Spectrum

2 longest wavelength shortest wavelength The Electromagnetic Spectrum The name given to a group of energy waves that are mostly invisible and can travel through empty space Longer waves have less energy Shorter waves have more energy and longer waves have less energy

3 Waves a review Most waves are either longitudinal or transverse. Sound waves are longitudinal. But all electromagnetic waves are transverse

4 Electromagnetic waves Produced by the movement of electrically charged particles Can travel in a vacuum (they do NOT need a medium) Travel at the speed of light 300,000 km/s Also known as EM waves

5 Electromagnetic Waves Transverse waves without a medium! (They can travel through empty space)

6 Electromagnetic waves travel VERY FAST around 300,000 kilometres per second (the speed of light). At this speed they can go around the world 8 times in one second.

7 Electromagnetic Spectrum name for the range of electromagnetic waves when placed in order of increasing frequency RADIO WAVES INFRARED RAYS MICROWAVES ULTRAVIOLET RAYS VISIBLE LIGHT X-RAYS GAMMA RAYS

8 Notice the wavelength is long (Radio waves) and gets shorter (Gamma Rays)

9 RADIO WAVES Have the longest wavelengths and lowest frequencies of all the electromagnetic waves.

10 Types of EM Radiation Radiowaves lowest energy EM radiation

11 Global Positioning Systems (GPS) measure the time it takes a radio wave to travel from several satellites to the receiver, determining the distance to each satellite.

12 Radio waves Longest wavelength EM waves Uses: TV broadcasting AM and FM broadcast radio Heart rate monitors Cell phone communication MRI (MAGNETIC RESONACE IMAGING) Uses Short wave radio waves with a magnet to create an image

13 Radio waves Longest wavelength EM waves Uses: TV broadcasting AM and FM broadcast radio Heart rate monitors Cell phone communication MRI (MAGNETIC RESONACE IMAGING) Uses Short wave radio waves with a magnet to create an image

14 MICROWAVES Have the shortest wavelengths and the highest frequency of the radio waves.

15 Microwaves Wavelengths from 1 mm- 1 m Uses: Microwave ovens Bluetooth headsets Broadband Wireless Internet Radar GPS

16 RADAR (Radio Detection and Ranging) Used to find the speed of an object by sending out radio waves and measuring the time it takes them to return.

17 INFRARED RAYS Infrared= below red Shorter wavelength and higher frequency than microwaves.

18 Infrared Radiation Wavelengths in between microwaves and visible light Uses: Night vision goggles Remote controls Heat-seeking missiles

19 VISIBLE LIGHT Shorter wavelength and higher frequency than infrared rays. Electromagnetic waves we can see. Longest wavelength= red light Shortest wavelength= violet (purple) light

20 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

21 When light enters a new medium it bends (refracts). Each wavelength bends a different amount allowing white light to separate into it s various colors ROYGBIV.

22 ULTRAVIOLET RAYS Shorter wavelength and higher frequency than visible light Carry more energy than visible light

23 Ultraviolet Shorter wavelengths than visible light Uses: Black lights Security images on money Harmful to living things Used to sterilize medical equipment Too much causes sun burn Extremely high exposure can cause skin cancer

24 Shorter wavelength and higher frequency than UV-rays Carry a great amount of energy Can penetrate most matter. X- RAYS

25 X-rays Tiny wavelength, high energy waves Uses: Medical imaging Airport security Moderate dose can damaging to cells

26 Bones and teeth absorb x-rays. (The light part of an x-ray image indicates a place where the x- ray was absorbed)

27 Used by engineers to check for tiny cracks in structures. The rays pass through the cracks and the cracks appear dark on film.

28 GAMMA RAYS Shorter wavelength and higher frequency than X-rays Carry the greatest amount of energy and penetrate the most.

29 Gamma Rays Smallest wavelengths, highest energy EM waves Uses Sterilizes medical equipment Cancer treatment to kill cancer cells Kills nearly all living cells.

30 Used in radiation treatment to kill cancer cells. Can be very harmful if not used correctly.

31 Exploding nuclear weapons emit gamma rays.

32 Brief SUMMARY A. All electromagnetic waves travel at the same speed. (300,000,000 meters/second) in a vacuum. B. They all have different wavelengths and different frequencies. Long wavelength- lowest frequency Short wavelength highest frequency The higher the frequency the higher the energy.