## The Importance of Black Body Radiation (?)

(Wien's law: $T\lambda _{max}=\frac{1}{5}C_{2}$ )

VGonzalez
Posts: 30
Joined: Fri Sep 28, 2018 12:18 am

### The Importance of Black Body Radiation (?)

In Monday's notes we wrote that the description if light as photons explains the intensity profile of black body radiation but have yet to talk about it again. Are we supposed to know the concept/definition of black body radiation? Is there any importance or significance to black body radiation?

Amy Lefley 1J
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

### Re: The Importance of Black Body Radiation (?)

Although I do not think we need to know much detail on black body radiation, I think it is helpful to know that it is an object that absorbs all wavelengths of light. This is a conceptual idea, and I do not think there actually exists an object that can absorb all wavelengths, just the majority.

Rachel Dang 1H
Posts: 32
Joined: Fri Sep 28, 2018 12:17 am

### Re: The Importance of Black Body Radiation (?)

Don't know if this is how it's defined in this class but you can think of it as what happens when a massive bulky object that absorbs all radiation and then emits its own form of radiation. One example would be like a burner of an oven that heats up and changes color as it gets hotter from black to red hot.

Kayla Vo 1B
Posts: 60
Joined: Fri Sep 28, 2018 12:26 am

### Re: The Importance of Black Body Radiation (?)

During lecture it was said that black body radiation will not be discussed much during the course. However it would be good to be familiar of what it is regardless

Casandra
Posts: 65
Joined: Fri Sep 28, 2018 12:17 am

### Re: The Importance of Black Body Radiation (?)

VGonzalez wrote:In Monday's notes we wrote that the description if light as photons explains the intensity profile of black body radiation but have yet to talk about it again. Are we supposed to know the concept/definition of black body radiation? Is there any importance or significance to black body radiation?

Grasping the black body concept would be helpful just because it relates to how the concept of quanta came to be.
A black body is an ideal incandescent source, meaning it is a perfect emitter and a perfect absorber of light.
This resulted in the ultraviolet catastrophe, which was that a theory that anything hot would emit UV radiation, this didn't match the results. Because that would mean that humans would emit radiation, which we don't.
Therefore, the concept of quanta came to be, that energy was released in packets by black bodies. This also led to Planck's constant and the equation of E=hv.

Henry Dudley 1G
Posts: 61
Joined: Fri Sep 28, 2018 12:16 am

### Re: The Importance of Black Body Radiation (?)

Rachel Dang 1H wrote:Don't know if this is how it's defined in this class but you can think of it as what happens when a massive bulky object that absorbs all radiation and then emits its own form of radiation. One example would be like a burner of an oven that heats up and changes color as it gets hotter from black to red hot.

Is this an actual example of a true black body? I thought they existed only in theory.