• LordCalculus
In summary, the problem requires calculating the energy per second radiated by the average person as blackbody radiation, using the Stefan-Boltzman law with the person's skin temperature of 306 K and the room temperature of 293 K. The energy radiated per unit time can be found using the equation dQ/dt = eAσT^4, where T is in Kelvin and e is the area of skin. However, this is not the same as the total energy lost per second, which would also take into account the energy absorbed.
LordCalculus

## Homework Statement

The average person has 1.4 m^2 of skin at a skin temperature of roughly 306 K. Consider the average person to be an ideal radiator standing in a room at a temperature of 293 K.

a.) Calculate the energy per second radiated by the average person in the form of blackbody radiation. Express you answer in watts. (How do I treat the temperature?)

## Homework Equations

L=AσT^4

Where A = area; σ = Stefan-Boltzmann constant; T = temperature (in Kelvins).

## The Attempt at a Solution

L=(1.4)*(5.670400*10^-8)*(?)^4

The energy per second radiated will just be that equation with body temperature as T (~310 Kelvin); but note that this isn't the same as the total energy lost per second.

Energy radiated per unit time will be given by Stefan-Boltzman law -

dQ/dt = eAσT^4 (σ - Stefan's constant)

but here 'T' is to be taken in Kelvin and not degree celsius.

and also this is not the energy lost since energy lost = (Energy radiated)-(Energy absorbed)

put T value in the equation. For heat radiated T=306 and for absorbed T=293

## 1. What is blackbody radiation and why is it important?

Blackbody radiation refers to the electromagnetic radiation emitted by a perfectly black object at a specific temperature. It is important because it helps us understand the behavior of light and heat, and has applications in fields such as astrophysics and thermodynamics.

## 2. How is blackbody radiation calculated?

Blackbody radiation can be calculated using Planck's law, which describes the spectral energy density of blackbody radiation at a given temperature. It involves using the wavelength of the emitted radiation and the temperature of the object to determine the amount of energy being emitted.

## 3. What is the Stefan-Boltzmann law and how is it related to blackbody radiation?

The Stefan-Boltzmann law states that the total energy emitted by a blackbody is proportional to the fourth power of its absolute temperature. This is directly related to blackbody radiation because it helps us understand how the intensity of the radiation changes with temperature.

## 4. How does the color of an object affect its blackbody radiation?

The color of an object is determined by the wavelengths of light it reflects. A blackbody absorbs all incoming radiation, so the color does not affect the amount of radiation it emits. However, the color can affect the distribution of the emitted radiation, with hotter objects emitting shorter, more energetic wavelengths.

## 5. Can blackbody radiation be seen in everyday life?

Yes, blackbody radiation can be seen in everyday life. For example, the glow of a hot metal object is due to blackbody radiation. Also, the colors of stars are determined by their blackbody radiation at different temperatures. Even our own bodies emit blackbody radiation in the form of infrared light.

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