# Calculating the strength of a magnetic field in a electromagnet

• balexan
In summary, Ben is investigating the effects of varying field strengths on the germination of seeds and the rooting of cuttings. He is looking for a formula to calculate the field strength. He is also considering using a long solenoid to measure the field.
balexan
hi all,

i have just signed up to this site to find some assistance with the above topic.

i am building an electromagnetic propagator to study the effects of varying field strengths on the germination of seeds and the rooting of cuttings.

it has been many years since i last look into such a topic, and i need some help with my calculations.

would someone be kind enough to give me the formula for calculating the field strength produced by an electro magnet (this is my variable). i am only using the simplist of apparatus i.e. an iron core, insulated copper wire, a transformer (this experiment is for 12v only) and sodium lamps.

Ben

Field strength where? In general, that is a hard problem to analyze in theory.

well, the electromagnet will be placed immediately under the seeds and/or cuttings. So the distance between the magnet and the sample will be no more than 15mm
I had hoped that there would be a formula to calculate the strength of the field using the current, length of wire and the number of turns , in addition to the size of core
it is possible that this may not be as easy as i had first thought, but i am keen to run the experiment in this manner as it provides the ability to alter the field strength over a number of different experiments run at the same time
Thanks

This thread might be interesting, together with some formulas for electromagnets with a core.

I had a thought that you could probably use the formula for the field inside a long solenoid - if you used a large area solenoid below and above the seed tray. The field would hardly be different from what you calculate if the gap is not great compared with the diameter of the coils. There may be a problem with the lighting, though.
Of course, if you just use a large coil underneath, do a calculation based on the simple solenoid, you would be near the right answer. You could then actually measure the field with a Hall Probe to calibrate the system against the current you are using.

## 1. How do you calculate the strength of a magnetic field in an electromagnet?

The strength of a magnetic field in an electromagnet can be calculated by using the equation B = μ0 * (N * I) / L, where B is the magnetic field strength, μ0 is the permeability of free space, N is the number of turns in the coil, I is the current flowing through the coil, and L is the length of the coil.

## 2. What is the unit of measurement for magnetic field strength in an electromagnet?

The unit of measurement for magnetic field strength in an electromagnet is tesla (T) or gauss (G), with 1 T = 10,000 G.

## 3. How does increasing the number of turns in the coil affect the strength of the magnetic field?

Increasing the number of turns in the coil increases the strength of the magnetic field. This is because more turns in the coil create a stronger magnetic force due to the increased number of loops that can interact with the magnetic field.

## 4. What is the relationship between current and magnetic field strength in an electromagnet?

In an electromagnet, the strength of the magnetic field is directly proportional to the amount of current flowing through the coil. This means that as the current increases, the magnetic field strength also increases, and vice versa.

## 5. How does the length of the coil affect the strength of the magnetic field in an electromagnet?

The length of the coil has an inverse relationship with the strength of the magnetic field in an electromagnet. This means that as the length of the coil increases, the magnetic field strength decreases, and vice versa. Therefore, shorter coils will have a stronger magnetic field than longer coils.

• Electromagnetism
Replies
41
Views
4K
• Electromagnetism
Replies
7
Views
2K
• Electromagnetism
Replies
10
Views
427
• Electromagnetism
Replies
198
Views
11K
• Electromagnetism
Replies
2
Views
2K
• Electromagnetism
Replies
43
Views
2K
• Electromagnetism
Replies
2
Views
870
• Electromagnetism
Replies
3
Views
1K
• Electromagnetism
Replies
8
Views
1K
• Electromagnetism
Replies
1
Views
823