Physics [Chapter 5.08]

Question	Answer
What is Thermal Radiation ?	It is energy in the form of electromagnetic waves that heat up things that absorb them (energy).
Thermal Radiation	When a surface is hotter and its surface area is larger, the more energy is radiated per second.
Emitters	An emitter is a surface that sends out thermal radiation. Eg. a black saucepan
Absorbers	An absorber is a surface that traps thermal radiation. Good emitters are also good absorbers. Meaning if a matt black saucepan were a good emitter, it is also a good absorber.
Greenhouse Effects	When the thermal radiation from the sun hits the earth, the atmosphere traps it in. It happens because some gasses absorb energy of certain wavelengths. This heat trapping action is called greenhouse effect.
The Solar Panel	Solar panels in houses use the sun's thermal radiation to warm up water. The blackened layer of the solar panel absorbs the energy and heats up the water in the pipes of the storage tank for water.
The Vacuum Flask	It keeps drinks at their initial temperature for hours. It has features that reduces the rate of thermal energy that flows in or out. Such as : An insulated stopper that reduces conduction and convection A double-walled container that reduces conduction and convection Walls with slivery surfaces to reduce thermal radiation.

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	Created by Sarah Loon over 6 years ago