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Thermal Conductivity, Stefan Boltzmann Law, Heat Transfer, Conduction, Convecton, Radiation, Physics

592 ratings | 86117 views
This physics video tutorial explains the concept of the different forms of heat transfer such as conduction, convection and radiation. It also shows how to calculate the rate of heat flow using thermal conductivity, emissivity, and the stefan boltzmann law of radiation equation. It shows the relationship between thermal conductivity and the insulation r-value of building materials. This video contains plenty of examples and practice problems.
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Text Comments (32)
Kayla (25 days ago)
At 22:07, why did you use 4piR^2 (surface area of a sphere) rather than the area of a sphere, piR^2?
Mika Korhonen (12 days ago)
His example is three dimensional object and will radiate energy (heat) equally to every direction.
Richael Mosen (1 month ago)
Why is K used to represent the rate of conductivity? Very confusing because K is used in many ways. I've learned to use greek letter Lambda
Richael Mosen (13 days ago)
+Ibewarri Lawrence exactly, so it's very confusing to use it to specify rate of conductivity. Makes no sense. Just use lambda instead
Ibewarri Lawrence (13 days ago)
K means kelvin which is stand for temperature
zed nes (2 months ago)
Is that a D or a triangle?
Freedom Kongvold (2 months ago)
Wow..I have watched this 2 times and still can't wrap my head around it. I'm trying to figure out if a heat source of 600f is 6 inches away from a sheet of 032 gauge aluminum and it's 100f air temp, how hot will the aluminum get? Then I need to figure out if a sheet of 1/8" vinyl is 1" away from the aluminum what is the max temp the vinyl will get? I have tried to figure this and my brain is stumped. My expertise is in other areas. Any guidance to offer?
Mika Korhonen (12 days ago)
This is basically new stuff for me too, but sounds impossible to solve without knowing size of the heat radiation source.
Juho Laaksonen (5 months ago)
I'm trying to solve this in a dynamic environment and would love a skype session to mirror ideas =D
Philangezwi Liwa (6 months ago)
Is it not R=L/KA?
Jasmine Wang (7 months ago)
Many thanks for this video! Really helpful
Ted Graves (8 months ago)
Q: For the passive transfer of heat, steel appears better then glass; which radiates faster. . .? Solar energy issue I am working on.
FreebieCatch (11 months ago)
Hello, at 25:11, the answers were both positive and negative. Could you please explain how you arrived at that? Thanks
Aditya Srivatsa (7 months ago)
for emitting we have to use -ve sign. All we're doing is seeing the NET ENERGY CHANGE. so if body is losing energy,it's obviously -ve sign
Stephen Hawks (10 months ago)
FreebieCatch one was negative, since for absprbtion we have to use a minus sign
real algeria (1 year ago)
At 28:57 why we put the same (e) for both air and sphere sence we have tow different materials??
real algeria e defined for body not for surrounding in the question
PEWDSSS1 (1 year ago)
thank you!
Syed Mudasir (1 year ago)
But i was told R=L/KA
@Bree McNeish (1 year ago)
thank you this helped me study for a big test
Todd David (1 year ago)
Sir I would like to like all your videos without watching them but there is no way I can do that.
shys (4 months ago)
You should watch all of them
Kyle S (1 year ago)
If I have a foil lined lunch box that I want to keep cool how should I go about calculating the heat loss due to radiation?
Edwin Beraud (23 days ago)
convection too. air is also cooling it.
Emma Najibi (1 year ago)
I appreciate your videos
Conrrr N/A (1 year ago)
very good except 1*10^n is incorrect format, standard and engineering form both day you don't write "1*" because that would be stupid as multiplying by 1 changes nothing
Larry Gilbert (4 months ago)
+Emma Najibi o
Emma Najibi (1 year ago)
that's really all you had to say about the entire video..? Just be grateful he uploaded the video. You obviously wanted/needed  to learn something or you wouldn't have watched the video all the way through.
Suhrab Jorashev (1 year ago)
area of circle isn't it п(R^2)
Jasmine Wang (7 months ago)
But the surface area of a sphere is 4piR^2
Yes, the area of a circle is pi(R)^2
avinash soni (2 years ago)
thank you so much sir... was waiting for this from a long time... sir when mordern physics lectures will be coming ?

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