# What is stefan: Definition and 11 Discussions

Ștefan is the Romanian form of Stephen, used as both a given name and a surname. For the English version, see Stefan.
Some better known people with the name Ștefan are listed below. For a comprehensive list see All pages with titles beginning with Ștefan.
Notable persons with that name include:

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1. ### Thermal lattice Boltzmann model ignoring source term -- python code help please

LBM model for phase change- relevant equations found here. Also here. #Thermal LBM #solves 1D 1 phase phase-change #D2Q5 Lattice nx=100 # the number of nodes in x direction lattice direction ny=5 # the number of nodes in y...
2. ### A Use of the Stefan Boltzmann Law in a Non Equilibrium system?

Hi everyone, I am currently trying to work something out in regards to non-equilibrium thermodynamics. If I have a block of metal in vacuum that is being heated by a laser with a constant power P, is it even possible to be able to describe the emission of radiation by the block via the Stefan...

4. ### Validate the Stefan Boltzmann equation

Homework Statement You are performing an experiment to validate the Stefan Boltzmann equation. What irradiance would you measure at a temperature of 109C? The emissivity of your thermal heat source is 0.81 and your thermopile measures 0 W/m2 at 27 C when directed towards a blackbody. Submit...
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### B Understanding Stefan Boltzmann Law: Derivation and Simulation Guide

Hello, everyone, I was looking at this video () and I need to make a simulation for Stefan Boltzmann law calculating its constant. I didn't understand few things. In the video, it shows that Stefan Boltzmann law is R = e*sigma*T^4vand then says that rate of net heat transferred ΔQ/Δt =...
6. ### B The shape of the body in Stefan Boltzmann Law modern use

Hello, It looks like Stefan Boltzmann Law can be used for a lot of different purposes: to calculate the temperature of stars, sun, temperature of the Earth's sky, temperature of particular surface, wall, the radiation emitted by the body by knowing its temperature, and so on. What confuses me...
7. ### Is the Stefan-Boltzmann Law Related to Black Body Radiation?

Hi, My textbooks says that "Josef Stefan investigated the increasing brightness of a black body as it is heated and discovered that the total intensity of radiation emitted over all wavelenghts increases as the fourth power of the aboslute temperature" MY question is this: Is the "total...
8. ### From Planck's law to derive the stefan Boltzman constant.

The following is the Planck's derivation for black body radiation $${\rho}({\lambda}) d{\lambda}=E({\lambda})*f({E(\lambda}))*D({\lambda})d{\lambda}------equation 1$$ $$\int_0^\infty{\rho}({\lambda})d{\lambda}$$ is the density of radiative energy. From...
9. ### Thermal equilibrium through radiation and Stefan Boltzmann

Hey Guys, so I had a longish discussion with colleagues and on reddit about thermal equilibrium and the sun and how you cannot heat up anything above the surface temperature of the sun using clever mirrors and stuff. However, somebody came up with Napkin calculations of the Stefan Boltzmann...
10. ### Why are there two Stefan Boltzmann Laws in Reif's book?

In Reif's book Fundamentals of Statistical and Thermal Physics, he labels two formulas as the Stefan-Boltzmann Law. They are both involve T^4 but the constant is different. In one, on page 376, the law is given as (pi2/15)*(kT)4/(c*hbar)3. The other, on page 388, is...
11. ### Is it possible - Stefan Boltzman Law

I have an intensity graph versus wavelenght of the light emited by two stars. For one of stars the curve of the graph temperature is 12000 K; for the other 3000 K. Is it possible, only from this data, to know which star will die first? Thanks