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Black Body?

Posted: Thu Oct 12, 2017 5:11 pm
by Daniel Rivas 3L
I was just wondering if someone can explain what a black body is to me? Like is it just a thing that is extremely hot? And why is it called a black body if it is usually a glowing white object?

Re: Black Body?

Posted: Thu Oct 12, 2017 5:38 pm
by Alex Kashou
A black body is any object that can absorb any incoming light. It is emits thermal heat due to its high absorption rate. However, if it gets too hot it starts to emit light (glow) from increased amounts of thermal radiation. Thus, all you really need to know is that it is a black body that can absorb any incoming light unlike other objects (typically tested with metals).

Re: Black Body?  [ENDORSED]

Posted: Thu Oct 12, 2017 11:19 pm
by Ramya Lakkaraju 1B
The term black body came about since these objects appear black in color at room temperature. They absorb all light and do not reflect any light.

Re: Black Body?

Posted: Fri Apr 13, 2018 7:13 pm
by Madeleine Farrington 1B
When you say that black bodies absorb all light, do you mean all light in the visible spectrum, or the entire electromagnetic spectrum?

Re: Black Body?

Posted: Fri Apr 13, 2018 11:10 pm
by Liliana Rosales 1E
I believe black bodies absorb the entire electromagnetic spectrum not just the visible spectrum.

Re: Black Body?

Posted: Sat Apr 14, 2018 9:33 am
by Mei Blundell_1J
Fun fact related to this topic: the Sun is a really efficient black body.

Re: Black Body?

Posted: Sat Apr 14, 2018 7:29 pm
by Sarai Viveros 1K
Could you explain how the sun is a black body?

Re: Black Body?

Posted: Sat Apr 14, 2018 7:36 pm
by Shimran Kumar 1C
So as the second post under this topic explains, black bodies absorb all light in the electromagnetic spectrum and emit thermal radiation. However, when they get too hot, they emit light.

The sun follows this definition. The sun is very hot, so it emits light. As large stars cool down and die, they can become black holes. Black holes are known for absorbing everything. Thus, suns/stars are black bodies.

Re: Black Body?

Posted: Sun Apr 22, 2018 4:43 pm
by Gabi Landes 1-H
Liliana Rosales 1E wrote:I believe black bodies absorb the entire electromagnetic spectrum not just the visible spectrum.


They do! A black body is an object that absorbs all radiation falling on it, at all wavelengths.

Re: Black Body?

Posted: Sun Apr 22, 2018 8:37 pm
by Vienna Cimetta 1L
Do you guys think we would be asked any questions on this topic? Or is it just another concept to know for future reference

Re: Black Body?

Posted: Sun Apr 22, 2018 8:41 pm
by Mohamad Farhat 1L
I had a similar question to this one. I was curious how when wearing a black shirt on a hot day absorbs more heat.

Re: Black Body?

Posted: Sun Apr 22, 2018 8:44 pm
by Chem_Mod
Please see Dr. Lavelle's class website for more information regarding test 2. He pointed this out during Friday's lecture to the class.
https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=18&t=30872

Re: Black Body?

Posted: Mon Apr 23, 2018 12:43 am
by vivianndo_1L
Could someone please explain the relationship between the ultraviolet catastrophe and black bodies then?

Re: Black Body?

Posted: Mon Apr 23, 2018 9:03 am
by Jamie Reniva 1J
Why is it called black body?