Electromagnetic Waves (EM Waves)
5/21/2014Electromagnetic Waves (EM Waves) EM waves consist of oscillating electric and magnetic fields. EM waves are transverse waves that carry energy in the formof radiation.The energy is called a photon- small packet of energyWave-Speed Equation c The speed of light (3.00 x 108 m/s) f Frequency in Hertz (Hz) λ wavelength (m) c f λ λ c/fRadio Waves Radio waves have thelongest wavelengths and theshortest frequencies in theelectromagnetic spectrum.MRI MRI uses radio waves Radio waves carry signals toyour stereo, television, andcellular phone.1
5/21/2014Microwaves Microwaves have wavelengths that can bemeasured in centimeters. Shorter microwaves are used in remotesensing. These microwaves are used forradar like the Doppler radar in weatherforecasts.DeforestationHow A Microwave Oven Works Alternating positive andnegative charges among theelectric and magnetic fields. Friction among thecolliding polarmolecules. An increase in kineticenergy results in heatingthe frozen food.Infrared Waves Infrared light lies between the visible andmicrowave portions of the electromagneticspectrum. Can not be seen but felt As heat Near infrared is the region closest in wavelength tothe radiation detectable by the human eye, whilemid and far infrared are progressively further fromthe visible spectrum.2
5/21/2014Temperature of stars Tell by the color Hottest stars are blue Coolest stars are red Find the wavelength to determine temperature Sun is 5800K Red dwarfs are about 3500k Blue stars start at 10,000k Largest blue giants are 40,000k- could actually becalled ultraviolet starsVisible spectrum (just a sliver!)Visible LightVisible light waves are the onlyelectromagnetic waves we can see.We see these waves as the colors ofthe rainbow. Each color has a different Visiblelight wavesarehasthe onlywavelength.Redthe electromagneticlongestwaveswe can see.wavelengthand violet has the shortestwavelength. When all the waves are Each color has a different wavelength. Red has theseen together, they make white light.longest wavelength and violet has the shortestwavelength. When all the waves are seen together,they make white light.3
5/21/2014What are stars made of Each element has a different spectralemission line Scientist look at the spectral lines of stars These lines tell us what the star is made ofWhat are stars made ofWhat are stars made of4
5/21/2014Red shift (Doppler effect) Doppler effect also works with light waves Moving towards shortens the wavelength Moving away lengthens the wavelength Towards is blue shift Away is red shiftAurora Borealis Sun emits energy or photons Earths magnetic field protects us from damagingenergy Solar flares release large amounts of energy5
5/21/20146
5/21/2014Ultraviolet waves Ultraviolet (UV) light is invisible to thehuman eye. Scientists have divided theultraviolet part of the spectrum into threeregions: the near ultraviolet, the farultraviolet, and the extreme ultraviolet.Ultraviolet waves UVA- longer wavelength, most of the UV light to reachthe ground UVB- main cause of sunburn, most blocked by ozone UVC- most harmful, all blocked by ozone layer 115,000feet up Most harmful UV light is absorbed by nitrogen Our Sun emits light at all the different Ozone is very important to life on earthwavelengths in electromagnetic spectrum,but it is ultraviolet waves that areresponsible for causing our sunburns.Ozone cycleO2 ℎνuv 2OO O2 O3X-rays We usually talk about X-rays in terms oftheir energy rather than wavelength. This ispartially because X-rays have very smallwavelengths. As the wavelengths of light decrease, theyincrease in energy. X-rays have smallerwavelengths and therefore higher energythan ultraviolet waves.7
5/21/2014Gamma RaysX-rays Cary enough energy to harm living tissue Can increase the risk of cancer Also used to kill cancer cells Rays can not penetrate lead Gamma-rays have the smallestwavelengths and the most energy ofany other wave in the electromagneticspectrum. These waves are generated byradioactive atoms and in nuclearexplosions.Ray Model of LightThe Grand Finale of Review insong, courtesy of Woo Fong Simplest explanation for how light travels http://www.youtube.com/watch?v kOkv8ynpppk&fea Assumption that light travels in a straight line path,ture relatedwhich make up rays Used to simply show the direction light waves areemitted from an object8
electromagnetic waves we can see. We see these waves as the colors of the rainbow. Each color has a different wavelength. Red has the longest wavelength and violet has the shortest wavelength. When all the waves are seen together, they make white light. Visible light waves are the only electromagnetic waves we can see.
Properties of EM Waves Electromagnetic waves are transverse waves Electromagnetic waves travel at the speed of light Because em waves travel at a speed that is precisely the speed of light, light is an electromagnetic wave Electromagnetic waves carry energy as they travel through space, and this energy can be transferred to objects
Waves and Thermodynamics MASTERING PHSICS 3.4 Electromagnetic Waves Conduct investigations to explain and analyse differences between mechanical and electromagnetic waves. Electromagnetic waves Electromagnetic transverse waves are different from transverse matter waves in that they: Can travel through a vacuum.
electromagnetic waves, like radio waves, microwaves, light, and x-rays are examples of transverse waves. Longitudinal waves travel through a medium in a direction parallel to the direction of travel of the wave. Mechanical waves such as sound waves, seismic waves created by earthquakes, and explosions are all examples of longitudinal waves.
The Electromagnetic Spectrum Light waves aren’t the only kind of electromagnetic waves. In fact, there is an entire spectrum of electromagnetic waves, as shown in Figure 18. The electromagnetic spectrum is the com-plete range of electromagnetic wave frequencies and wavelengths. At one end of the
Electromagnetic Spectrum: Radio Waves and Microwaves Electromagnetic waves are created when charged particles move, and these waves occur along a spectrum of different wavelengths. Although the electromagnetic spectrum is continuous, scientists divide it into seven sections based on wavelength. Radio waves have very long wavelengths, and
Q: What are mechanical waves? A: Waves that require a medium in which to travel. A medium is the _ that waves travel through o Mediums can be solid, liquid, or gas Examples of mechanical waves include sound waves, seismic waves, ocean waves, etc Q: Describe two types of mechanical waves.
Electromagnetic Waves Waves that DO NOT NEED matter (medium) to transfer energy Examples: radiation, TV & radio waves, X-rays, microwaves, lasers, energy from the sun, visible light Electromagnetic waves are considered transverse waves because they have simi
Anatomi tulang pada tangan, terdiri atas tulang lengan atas (humerus), pergelangan tangan (carpal), telapak tangan (metacarpal), dan jari-jari. Setiap lengan melekat pada tulang belikat (scapula), yaitu tulang segitiga besar di sudut tulang bagian atas setiap sisi tulang rusuk. Kerangka tubuh terdiri atas berbagai jenis tulang yang memiliki fungsi dan bentuk yang berbeda untuk menjalankan .
