the nature of electromagnetic waves. electromagnetic radiation emr requires no medium to travel-...
TRANSCRIPT
Electromagnetic RadiationElectromagnetic Radiation
EMR requires no medium to travel- EMR requires no medium to travel- can travel thru a vacuumcan travel thru a vacuum
SpeedSpeed300,000 kilometers /sec300,000 kilometers /sec186,000 miles /sec186,000 miles /sec
Consists of changing electric and Consists of changing electric and magnetic fieldsmagnetic fields
Changing electric and magnetic fieldsChanging electric and magnetic fields Electric field is a region where particles can be pushed or pulled.Electric field is a region where particles can be pushed or pulled.
Wherever there is an electric charge there is an electric field Wherever there is an electric charge there is an electric field associated w/it.associated w/it.
A moving electric charge is part of an electric currentA moving electric charge is part of an electric current An electric current is surrounded by a magnetic fieldAn electric current is surrounded by a magnetic field
A magnetic field is a region in which magnetic forces are presentA magnetic field is a region in which magnetic forces are present When electric field changes – so does the magnetic field.When electric field changes – so does the magnetic field.
EMR - Wave or Particle?EMR - Wave or Particle? Acts like a wave sometimes – ie: Polarizing FilterActs like a wave sometimes – ie: Polarizing Filter
EMR - Wave or Particle?EMR - Wave or Particle? Acts like a particle, a photon, sometimes – ie: Photoelectric CellActs like a particle, a photon, sometimes – ie: Photoelectric Cell
EMS wavesEMS waves Long wavelength : Low Frequency & Low EnergyLong wavelength : Low Frequency & Low Energy Short wavelength : High Frequency & High Energy Short wavelength : High Frequency & High Energy
Radio & MicrowavesRadio & Microwaves Longest wavelengths & Longest wavelengths &
lowest frequency of the lowest frequency of the EMSEMS– Include Include Am, FM and Am, FM and
TelevisionTelevision frequencies frequencies AMAM – – Amplitude Amplitude
modulationmodulation: same : same frequency waves just a frequency waves just a change in the amplitude change in the amplitude to get different sounds to get different sounds etc.etc.
FMFM – – Frequency Frequency ModulationModulation: slight : slight changes in frequencychanges in frequency
Microwave & Infrared EMRMicrowave & Infrared EMR MicrowaveMicrowave: used in microwave ovens & cellular : used in microwave ovens & cellular
phonesphones InfraredInfrared: Fast Food Heat Lamps, use as a night : Fast Food Heat Lamps, use as a night
time surveillance tool.time surveillance tool.
Visible LightVisible Light White light is a mixture of the entire visible light White light is a mixture of the entire visible light
spectrumspectrum
UV, Xray & Gamma raysUV, Xray & Gamma rays UVUV from the Sun helps the body produce vitamin D, too from the Sun helps the body produce vitamin D, too
much exposure can cause skin cancer much exposure can cause skin cancer XraysXrays: used extensively in medicine to see “into” the body: used extensively in medicine to see “into” the body Gamma RaysGamma Rays: used in medicine to treat cancer or : used in medicine to treat cancer or
destructive radiation from nuclear explosions.destructive radiation from nuclear explosions.