# Magnetic Fields and Current experiment

• mer584
In summary, this experiment is being done near an electric cable with a current limit. If the magnetic field from the nearby wire is within 0.01 of the Earth's magnetic field, then the current limit is allowed.
mer584
I put this in the intro forum about 3-4 hours ago and no one answered, can anyone here help?

1. Homework Statement
An experiment on the Earth's magnetic field is being carried out 1.00m from an electric cable. What is the maximum allowable current in the cable if the experiment is to be accurate to +/- 1.0%

2. Homework Equations
B= uI/2(pi)r
B is proportional to I/R where B is the magnetic field and pi=3.14
F=IBI where this is I one and I two.

3. The Attempt at a Solution
I'm not really sure to do without any numbers. Is there a way to find B so you can then use the first formula I listed to find I using R=1m.

Is there a way to express B in terms of that percentage? The answer is 2.5A

mer584 said:
I put this in the intro forum about 3-4 hours ago and no one answered, can anyone here help?

1. Homework Statement
An experiment on the Earth's magnetic field is being carried out 1.00m from an electric cable. What is the maximum allowable current in the cable if the experiment is to be accurate to +/- 1.0%

2. Homework Equations
B= uI/2(pi)r
B is proportional to I/R where B is the magnetic field and pi=3.14
F=IBI where this is I one and I two.

3. The Attempt at a Solution
I'm not really sure to do without any numbers. Is there a way to find B so you can then use the first formula I listed to find I using R=1m.

Is there a way to express B in terms of that percentage? The answer is 2.5A

I went ahead and deleted your post in Intro Physics, since you prefer the thread here. Keep in mind that it's Friday afternoon/evening for much of the world, so expecting replies in a couple hours may not be realistic.

Now, on to your problem. What is the magnitude and direction of the Earth's magnetic field (at least on the surface of the Earth on the main continents, where presumably this experiment is being carried out)? If you want to be able to measure that to within 1%, then you want the magnetic field from the nearby wire to be about 0.01 of the Earth's magnetic field. That tells you (via the equation that you mention for the magnetic field surrounding a current-carrying wire) how much current you can tolerate in the nearby cable.

O.K. I see it now. Thank you.

## 1. What is a magnetic field and how does it affect currents?

A magnetic field is an invisible force that surrounds a magnet or electric current. In the context of currents, a magnetic field can either be produced by a current or can induce a current. When a current flows through a wire, a magnetic field is created around the wire. This magnetic field can then interact with other nearby currents, causing them to either attract or repel each other.

## 2. How can magnetic fields be measured in a current experiment?

Magnetic fields can be measured using a device called a magnetometer. This device uses a compass needle or a Hall probe to detect and measure the strength and direction of a magnetic field. In a current experiment, a magnetometer can be used to measure the magnetic field produced by a current-carrying wire or the magnetic field induced by a changing current in a nearby wire.

## 3. What is the relationship between magnetic fields and electric currents?

Magnetic fields and electric currents are closely related. A magnetic field can be produced by an electric current, and a changing magnetic field can induce an electric current. This relationship is described by Ampere's Law and Faraday's Law of Induction, respectively. In a current experiment, these laws can be used to understand the behavior of magnetic fields and currents.

## 4. How do magnetic fields affect the behavior of charged particles in a current experiment?

In a current experiment, charged particles such as electrons or protons can be affected by the magnetic field produced by a current. When a charged particle moves through a magnetic field, it experiences a force perpendicular to both the direction of motion and the direction of the magnetic field. This force can cause the particle to change its direction of motion, resulting in a curved or circular path.

## 5. Can the strength of a magnetic field be changed in a current experiment?

Yes, the strength of a magnetic field can be changed in a current experiment. This can be done by varying the current in a wire or by changing the distance between the wire and a magnetometer. Additionally, the strength of a magnetic field can also be affected by the material surrounding the current, as different materials can either amplify or weaken the magnetic field.

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