Hope the study goes well. Had a request for more calculation based questions.
It’s found here, under the worksheet page.
Keep in mind the test will be pretty equal in terms of theory and calculations.
The only silly question is that which is not asked.
“Black radiates heat at a faster rate” is indeed true.
It is generally intuitive that black absorbs radiation at a faster rate. Black roads tend to feel hotter on bare feet than white concrete. What is less intuitive that it also works the other way. That is black objects give off more radiation than lighter colours.
If a black piece of metal and a white piece of metal were both heated to a high temperature, then left to cool, the black piece of metal will radiate more electromagnetic radiation than the white piece. If all else was equal, the black piece will reach room temperature before the white piece.
As another example, the radiator in a car is black. Its purpose is to emit radiation in order to cool the radiator fluid which has absorbed heat from the engine. It is black so that it can emit as much radiation as possible, not to absorb as much as possible.
Thanks Mr. P!
Hi Mr. Patterson,
This is a rather silly question but I noticed in the Heinemann book, it says that “Black radiates heat at a greater rate”
I’m guessing this means that black radiates heat faster, which means it will be colder. This is not true though, all the practise questions, and my own general knowledge says that black will be hotter, because it is slower to lose temperature.
Is this a speling mistake, or am I missing something?
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I've been working on updating all the videos and problem sheets for the new Physics WACE courses :
Unit 1 and 2 for year 11
Unit 3 and 4 for year 12
The new site has the unit 3 and 4 content ready to go.
Head on over to the new site if you are in year 12.
Find out more!