# Calculate the solenoid dimension

1. Apr 30, 2008

### mdpai

Hi to all,

I have a problem to share with you guys.

How can I calculate the thickness of my solenoid if I have these values;

Solenoid long : 20cm
magnetic field, B : 5Tesla
Current, I : 20A

Thanks a lot for your help. I appreciate that

2. Apr 30, 2008

### NoTime

3. Apr 30, 2008

### mdpai

5T, yeah I know , it's a lot. is it possible?

4. Apr 30, 2008

### mdpai

B=μnI this is only valid if the proportion between the thickness and the longeur is huge.

5. Apr 30, 2008

### NoTime

Since stronger magnets have been built, it's possible.
Within any construction constraints you might have, no idea.
Good luck with that.

6. May 6, 2008

### R A V E N

At which place is regarding to solenoid $$B=5\;T$$?

For example,formula for $$B$$ in center of solenoid is:

$$B=\frac{\mu_0NI}{\sqrt{4R^2+l^2}}$$

7. May 6, 2008

### mdpai

It's in the air at the center of the solenoid.

p/s:
I found a formula

$$B=\frac{\mu_0NI}{\sqrt{R^2+l^2}}$$

So now I confuse, it's 4R^2 or R^2?

8. May 7, 2008

### R A V E N

You are right,it is error in my book.But still you don`t have $$N$$ given.

9. May 7, 2008

### mdpai

the thickness of the solenoid depends on the value of N. So, I dont know if we have to calculate N first or, directly calculate the value of the thickness

10. May 7, 2008

### R A V E N

$$N$$ is number of loops.