Radiation

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akimhaneul

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How does radiation work in heat transfer?


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Like when you go outside and absorb those UV rays to get your tan on but it heats up your skin and is dangerous (mutagen)!
 
Radiation is just energy - so like UV light or gamma rays or even light. The energy hits a surface and excites particles to move. That moving causes an increase in the kinetic energy of those particles, or "thermal excitation," which results in an increase in temperature.
 
Radiation is just energy - so like UV light or gamma rays or even light. The energy hits a surface and excites particles to move. That moving causes an increase in the kinetic energy of those particles, or "thermal excitation," which results in an increase in temperature.

Can you say that out of three methods of heat transfer (conduction convection radiation) can you have more than one occurring at the same time?

For example, if you have a heater heating a room, can you say that both conduction and convection are occurring since the air particles are hitting each other to transfer energy and also moving as fluid?

Just wanted to clarify thanks!




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Can you say that out of three methods of heat transfer (conduction convection radiation) can you have more than one occurring at the same time?

Yes, of course you can have more than one occurring simultaneously! In fact, when you're boiling a pot of water, you have all three occurring at once. Radiation from the energy from the heating coils hitting the pot, convection from the water cycling up the pot and back down as it cools, and conduction as the hot water moves up and contacts the cooler water and sides of the pot.
 
Slight correction, whenever two bodies of different temperatures are in direct contact with each other, radiation heat transfer disappears as the heat is transferred via conduction. In fluids, this conductive transfer will spark convective, and in a open system, both hot bodies will radiate heat to the environment, but will not radiate between each other.


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