EM Radiation and Energy

EM Radiation and Energy

1. EM Radiation emmited from a source

   • Any object emitting radiation is called a source
   • The frequency of thermal radiation emitted from an object increases with temp
   • EM radiation travels at 300000km/s in a vacum

2. Transmission, Reflection and Absorption

   • Transmission: Radiaition carries on through (i.e. light passing through glass)
   • Reflection: Bounce back
   • Absorption: Absorb the energy
     • These are called detectors (i.e eyes are detectors of visible light)

3. Intensity Decreases as Distance from source increases

   • During absorption photons transfer energy to matter
   • Intensity is how much energy arrives at each square meter/s
   • Intensity decreases with distance due to the beam spreading out and it getting absorbed as it goes