# What does this symbol stand for?

1. ### Lorax

42
4πε0r^2

Thats 4pi (backwards 3 0) R squared.

I forget what the backwards 3 o stands for can someone help me out.

2. ### ascky

51
Backwards 3_0 thing is 'epsilon nought' or the permittivity constant.

3. ### Sirus

578
Backwards 3_0 thing = $\epsilon_{0}$

4. ### futb0l

0
"epsilon zero" i think it's called ... the permitivity of free space or something like that

5. ### chroot

10,427
Staff Emeritus
$$\epsilon_0 = 8.854187817 \cdot 10^{-12} F/m$$

It's called the "electric permittivity of free space," and commonly pronounced "epsilon-zero" or "epsilon-naught."

- Warren

6. ### DrTravia

3
lol thank you SO much :P helped me more than you know :P

7. ### ideasrule

2,323
A general rule is that weird-looking symbols are almost always Greek letters.

8. ### DrTravia

3
Knowing what they are and what they stand for are two completely different things

Knowing it's a greek letter lets us know they used it to write letters and the like, it gives us no clue at all as to what it pertains to in physics or other maths.

Obtaining a firmer grasp of the English language will be beneficial to your ability to understand the question that has been asked :)

9. ### Hurkyl

16,090
Staff Emeritus
Google searching on that returns a lot of hits. One might have the information you wanted. (I didn't dig into them)

Wikipedia searching on "ε0" returns exactly the page you wanted.

10. ### Ketman

42
His grasp seems firm enough to me. Telling the student that weird symbols are usually Greek letters is a useful addition to the exact answer given by a previous poster. Are you an information accountant?

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