Calculating the magnetic field in solenoid

In summary, the question is whether the length L in the formula for calculating the magnetic field of a solenoid would be the length of the solenoid or the length of the core if the core is made of steel and the coil only wraps around a small part of it. It is confirmed that L would be the length of the core, not the solenoid, as the magnetic flux through the core remains constant regardless of the turn density of the coil.
  • #1
rp8308
15
0
Just need a question cleared up.

If I had a coil wrapped around a core, and I was calculating the magnetic field of the solenoid using

B = μnI

where n = N/L, I is current and μ is the permeability of my material

N being the number of turns in the coil, and L being the length of the solenoid if there was an air core. Now if I had a steel core, for example, and the core was a large circular shape such that the coil itself only wrapped around a small amount of the core. Would the length L be the length of the solenoid still? (because its defined as turn density) or would it be the length that the magnetic flux takes through the whole core and therefore be the mean length of the core? (much larger than the length of the solenoid).

Cheers
 
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  • #2
ok I am pretty sure its the length of core because flux through the core won't change with the density of turns, but could do with someone just confirming this... I hate when i confuse myself
 
Last edited:
  • #3
If you meant to say L is the length of the coil, then yes I agree.

Edit: By 'length of the coil' I mean the length of the core which is surrounded by coil. (Not the actual length of the coil which is wrapping around it).
 

1. How do you calculate the magnetic field in a solenoid?

The magnetic field in a solenoid can be calculated using the equation B = u0 x n x I, where u0 is the permeability of free space, n is the number of turns per unit length, and I is the current flowing through the solenoid.

2. What is the direction of the magnetic field in a solenoid?

The direction of the magnetic field in a solenoid is determined by the right-hand rule. If you curl the fingers of your right hand in the direction of the current flow, your thumb will point in the direction of the magnetic field inside the solenoid.

3. How does the magnetic field vary along the length of a solenoid?

The magnetic field inside a solenoid is relatively uniform along its length, with the strongest field occurring at the center of the solenoid and gradually decreasing towards the ends. This is because the magnetic field lines are tightly packed and parallel to each other inside the solenoid.

4. Can the magnetic field inside a solenoid be affected by changing the current or number of turns?

Yes, the magnetic field inside a solenoid is directly proportional to the current and the number of turns. Increasing either of these parameters will result in a stronger magnetic field, while decreasing them will result in a weaker magnetic field.

5. How is the magnetic field in a solenoid affected by the presence of a ferromagnetic material?

The presence of a ferromagnetic material, such as iron, inside a solenoid can greatly increase the strength of the magnetic field. This is because the material becomes magnetized and adds to the overall magnetic field of the solenoid. However, the exact effect will depend on the type and placement of the material within the solenoid.

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