# Does a Blackbody at 200K Emit Twice as Much Radiation?

• clarkandlarry
In summary, the conversation discusses whether a blackbody at 200K emits twice as much radiation as when its temperature is 100K. The person suggests that this is true because the energy of the photons is doubled when the temperature is doubled. However, the other person mentions that there is an equation relating radiated power to temperature and suggests that it can be found in class notes or textbook. They also mention another equation involving radiated power and temperature raised to an integer power, possibly with a Greek lowercase "sigma."
clarkandlarry

## Homework Statement

Does a blackbody at 200K emit twice as much total radiation as when its temperature is 100K?

N/A

## The Attempt at a Solution

I'm not sure, but I think it is yes because if the temperature is doubled, then the energy of the photons will be doubled, therefore it will emit twice as much radiation. Is this correct?

There is a well-known equation that relates radiated power to temperature of a blackbody. It is surely in you class notes or textbook.

the only equation in my notes with temperature in it is:
(wavelength) x temperature = 0.002898mK

i don't know how this relates to the question though

There should be another equation, involving radiated power. And temperature raised to some integer power. It probably has a Greek lowercase "sigma" in it as well.

If not in your notes, check the textbook.

## 1. What is a blackbody?

A blackbody is an idealized object that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence. It also emits radiation based on its temperature.

## 2. What is the relationship between temperature and radiation emitted by a blackbody?

The amount and frequency of radiation emitted by a blackbody is directly proportional to its temperature. This relationship is known as the Stefan-Boltzmann Law.

## 3. How is the amount of radiation emitted by a blackbody at a specific temperature calculated?

The amount of radiation emitted by a blackbody at a specific temperature can be calculated using the Stefan-Boltzmann Law, which states that the power (energy per unit time) emitted by a blackbody is proportional to the fourth power of its absolute temperature.

## 4. Does the amount of radiation emitted by a blackbody double when its temperature is doubled?

Yes, according to the Stefan-Boltzmann Law, the amount of radiation emitted by a blackbody will increase by a factor of 16 (2 to the power of 4) when its temperature is doubled.

## 5. How does the concept of a blackbody relate to real-life objects?

While an ideal blackbody does not exist in nature, many objects can be approximated as blackbodies, such as stars and planets. Other objects may have varying degrees of reflectivity and emissivity, affecting their radiation emission properties.

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