# Field Strength

Status
Not open for further replies.

#### codan

##### New Member
Hi,

I am trying to calculate the magnetic field strength of an air core coil.

I have found the Permeabillity of Air is 1.256 x 10^-6,

My question is, for the 10^-6 is this just .00000010

so the Permeabillity of Air is 1.256 x .00000010

I am not sure, is this correct.

#### dougy83

##### Well-Known Member
No.

10^-6 (or 10E-6) is 0.000001

you should know that 10^0 is 1, and for every negative exponent you shift the decimal point to the left 1 digit. The opposite is true for positive exponents.

#### dknguyen

##### Well-Known Member
Didn't you ever learn about exponents? For negative exponents:

X^-Y = 1/(X^Y)

So:
10^-6 = 1/(10^6) = 1/1000,000

Last edited:

#### codan

##### New Member
Thanks for the replies.

No i haven't learnt about exponents as yet.
Another thing i am having trouble with is say i have.

1.0000000000000001e-11

I do not know what the e is or what number this actually is, how do i write this number without using the e or -11 as an example.

Thank You

#### dougy83

##### Well-Known Member
The 'e' stands for 'exponent' and may be directly substituted by 'x10^' (the 'x' is for multiplication, the '^' raises to a power)

So, 1.0000000000000001e-11 = 1.0000000000000001x10^-11

#### j.friend

##### New Member
That is more than a little confusing, why would they use 'e' to denote exponent when it is more widely recognised as the natural number e (which ≈ 2.718)?

#### jasonbe

##### New Member
Hi,

I am trying to calculate the magnetic field strength of an air core coil.

I have found the Permeabillity of Air is 1.256 x 10^-6,

My question is, for the 10^-6 is this just .00000010

so the Permeabillity of Air is 1.256 x .00000010

I am not sure, is this correct.
Just out of curiosity, are you using the same formula as that for a solenoid? Are you using relative permeability - which I think might be your figure, the Permeability of Air, divided by the permeability of free space, 4*pi * 10^-7 T*m/A? I like to use * instead of x because I don't always know when x is referring to a cross product. I just wanted to make sure that by writing T*m/A I meant units - not variables.

Last edited:
Status
Not open for further replies. 