Thermal Radiation

Thermal Radiation

1. Different surfaces

   • Absorbing thermal radiation
     • Matt black
   • Emitting thermal radiation
     • Matt black
   • Reflecting thermal radiation
     • Silver

2. Ways in which the thermal radiation changes when a warm object is heated

   • Emit shorter wave lengths
   • Radiate more infrared

3. Radiation is the transfer of heat by infra red waves. Infra red waves are part of the electromagnetic spectrum. They have a longer wave length than visible light.

4. Infra red

   • Unlike conduction and convection, infra red radiation does not require a solid, liquid or a gas to travel through, it can travel through a vacuum. This is how heat and light from the sun reaches the earth. Infra red radiation travels at the speed of light in a straight line.

5. a vacuum

   • A space in which there is no matter or in which the pressure is so low that any particles in the space do not affect any processes being carried on there.
     • Measured in the units of pressure
       • The pascal

6. Absorbing and emitting radiation

   • Hot object†s
     • emits more infrared radiation than it absorbs.
   • Cold objets
     • Absorbs more infra red than it emits.

7. Efficiency

   • Efficiency = Useful work done(output) total energy used (input)

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