What causes materials to heat up when energy is converted?

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Discussion Overview

The discussion revolves around the mechanisms by which materials heat up when they absorb energy, particularly focusing on electromagnetic radiation. Participants explore various types of radiation, such as visible light, infrared, and microwaves, and their effects on materials. The conversation includes both theoretical and practical considerations, with references to specific examples and contexts.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that materials heat up when they absorb electromagnetic radiation of any type, including visible light.
  • Others argue that specific types of radiation, such as infrared or microwaves, are more relevant to the heating process.
  • A participant mentions that certain materials, like glass, do not heat up when exposed to visible light because they are transparent to that frequency.
  • There is a discussion about superconducting antennas, with some participants questioning whether these antennas absorb energy or merely focus it, raising issues about the definition of absorption.
  • Another participant notes that in practical scenarios, energy conversion typically results in some heat loss, despite theoretical discussions about perfect efficiency.

Areas of Agreement / Disagreement

Participants express differing views on the types of radiation that cause heating and the definition of absorption. There is no consensus on a single explanation, and the discussion remains unresolved regarding the nuances of energy absorption and heating.

Contextual Notes

Some statements depend on specific definitions of absorption and may not account for all types of materials or radiation. The discussion includes hypothetical scenarios that may not reflect practical realities.

bubakazouba
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no its not a homework question it was in a quiz but i believe the teacher is wrong about it
materials are heated when they absorb:
-electromagnetic radiation of any type
-infrared radiation only
-microwaves and infrared only

please choose and explain
Thanks in advance
 
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What was your answer? Explain.
 
my answer was a)electromagnetic radiation of any type
I am in grade 10 IGCSE I don't have a lot of background in physics but I thought that visible light(which is part of the electromagnetic spectrum)is able to heat objects
like in lamps
and in nuclear fission when gamma radiation is emitted from the U-236 nuclei it heats the water to produce steam that runs the generator
 
That would be my answer too.

It is true that some materials are transparent to certain frequencies of radiation. But if that were true, then one would not say that the material absorbed that frequency.

So if it's absorbed at all, it will result in a rise in temperature.
 
Thanks for your quick reply
 
Last edited:
Your teacher may be thinking of examples like how a glass window is not heated by visible light. Well, that's because the light passes through the window; it is not absorbed.

And the question as you wrote it specifically says "absorbed".
 
I believe that will simplify many things,the question really did say "absorbed"
Man thanks a lot
and sorry for my poor english
 
A superconducting antena could absorb a radio signal without heating up. The energy would be passed along to the reciever without loss so energy in = energy out.

This opens up a debate about what constitutes "absorption". Does an antena absorb the radio wave and produce an electrical output or does it focus energy on the reciever like a lense or mirror?
 
mrspeedybob said:
A superconducting antena could absorb a radio signal without heating up. The energy would be passed along to the reciever without loss so energy in = energy out.

This opens up a debate about what constitutes "absorption". Does an antena absorb the radio wave and produce an electrical output or does it focus energy on the reciever like a lense or mirror?

The antenna itself would not absorb energy - the load to which it was connected would, however. If there were no resistive element involved, the EM would just be reflected / scattered. The whole receiving apparatus would not (could not - by definition) be a superconductor.
 
  • #10
guys I am lost
what does that mean?
 
  • #11
They were hypothesizing about some perfectly efficient way of converting radio waves into electrical energy without losing energy to heat. But, for all practical purposes, we always get some heat when we convert energy from one form to another.
 

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