Where Can I Find the Dimensional Analysis of Emissivity?

mikekyrou
Messages
10
Reaction score
0

Homework Statement



Does anyone know where can i find (book?) the dimensional analysis of emissivity?

Homework Equations





The Attempt at a Solution

 
Physics news on Phys.org
hi mikekyrou! :smile:

emissivity is a dimensionless ratio (i supppose it might be better called relative emissivity)

see http://en.wikipedia.org/wiki/Emissivity" …
The emissivity of a material (usually written ε or e) is the relative ability of it's [spelling!] surface to emit energy by radiation. It is the ratio of energy radiated by a particular material to energy radiated by a black body at the same temperature. A true black body would have an ε = 1 while any real object would have ε < 1. Emissivity is a dimensionless quantity.​
 
Last edited by a moderator:
Thanks for the reply tiny-tim. I know what is emissivity and i want to prove that emissivity is dimensionless. I know that is because is a ratio but i want to prove it through equations(dimensional analysis-using mass,length,time).
 
but if it's a ratio of two things that are the same dimensionally, then it has to be dimensionless
 

Thread 'Direction of the magnetic field of an oscillating charge'

Hello everyone, I’m considering a point charge q that oscillates harmonically about the origin along the z-axis, e.g. $$z_{q}(t)= A\sin(wt)$$ In a strongly simplified / quasi-instantaneous approximation I ignore retardation and take the electric field at the position ##r=(x,y,z)## simply to be the “Coulomb field at the charge’s instantaneous position”: $$E(r,t)=\frac{q}{4\pi\varepsilon_{0}}\frac{r-r_{q}(t)}{||r-r_{q}(t)||^{3}}$$ with $$r_{q}(t)=(0,0,z_{q}(t))$$ (I’m aware this isn’t...
View full post »

Thread 'Initial conditions for orbits around a wormhole'

Hi, I had an exam and I completely messed up a problem. Especially one part which was necessary for the rest of the problem. Basically, I have a wormhole metric: $$(ds)^2 = -(dt)^2 + (dr)^2 + (r^2 + b^2)( (d\theta)^2 + sin^2 \theta (d\phi)^2 )$$ Where ##b=1## with an orbit only in the equatorial plane. We also know from the question that the orbit must satisfy this relationship: $$\varepsilon = \frac{1}{2} (\frac{dr}{d\tau})^2 + V_{eff}(r)$$ Ultimately, I was tasked to find the initial...
View full post »

Similar threads

Dimensional analysis on an Ising model solution
Replies
9
Views
2K
Temperature difference by Dimensional analysis.
Replies
2
Views
1K
Using dimensional analysis to create dimensionless equation
Replies
4
Views
2K
Dimensional analysis of an equation
Replies
1
Views
2K
Dimensional analysis of an equation of motion
Replies
6
Views
2K
I What are the applications of dimensional analysis and why does it work?
Replies
5
Views
2K
Problems with Dimensional Analysis.
Replies
1
Views
3K
What are the momenta of particles in beta emission of C14?
Replies
1
Views
1K
I Dimensional analysis seems wrong for this equation: z = -1/(x^2+y^2)
Replies
7
Views
1K
Dimensional analysis to estimate gas clounds collapse
Replies
1
Views
1K

Hot Threads

Recent Insights

Back
Top