# Determine voltage from a conductor in magnetic field

• BBruyne
In summary, the conversation discusses the link between Faraday's law and motional EMF, as well as how to determine the induced electric field. The website provided explains how a loop of wire moving at a constant speed perpendicular to a magnetic field experiences a Lorentz force and induces an EMF, which can also be calculated using Faraday's law. The conversation also considers the scenario where a magnet is moved towards a stationary loop of wire, causing an induced EMF. This can be justified by considering the relative motion between the magnet and the loop, where the velocity of the loop is parallel to the magnetic field of the magnet.

#### BBruyne

Hi,

I would like to know how to get the potential difference due to a constant local magnetic field acting on a wire moving at a constant speed perpendicular to the field. What is the link between F = q v ∧ B and the actual difference of potential in the circuit ? How to determine the induced electric field ? I have attached an image to illustrate it.

Thank you,

Bbruyne

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• BBruyne
Thanks for the link, very nice website. I am learning Faraday's law and I am trying to link motional emf to his law. I do understand that a squared loop of wire of length l moving with a velocity v into a stationnary magnetic field B will experience a Lorentz force and this force will induce an emf. From emf = l v∧B, with a bit of manipulation, we arrive to emf = dΦ/dt. http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elevol.html#c3

That means that if the loop of wire is not moving but we approach a magnet into the loop, we get an induced emf. How can we justify this with the initial idea emf = l v∧B. We could say that the loop is moving relatively to the magnet but, it is moving in a parallel direction to the magnetic field of the magnet, thus v∧B = 0.

## 1. How does a conductor in a magnetic field create a voltage?

When a conductor is placed in a magnetic field, the magnetic field induces a current in the conductor. This current, in turn, creates a voltage in the conductor.

## 2. What factors affect the voltage created by a conductor in a magnetic field?

The voltage created by a conductor in a magnetic field depends on the strength of the magnetic field, the length of the conductor, and the velocity of the conductor moving through the magnetic field. It also depends on the angle between the direction of the magnetic field and the direction of the conductor's motion.

## 3. How can the voltage from a conductor in a magnetic field be measured?

The voltage from a conductor in a magnetic field can be measured using a voltmeter. The voltmeter is connected to the ends of the conductor, and the voltage can be read directly from the voltmeter.

## 4. Can the direction of the conductor's motion affect the voltage created?

Yes, the direction of the conductor's motion can affect the voltage created. The voltage will be at its maximum when the conductor moves perpendicular to the magnetic field and will be zero when the conductor moves parallel to the magnetic field.

## 5. What is the relationship between the voltage and the rate of change of the magnetic field?

The voltage created by a conductor in a magnetic field is directly proportional to the rate of change of the magnetic field. This means that as the magnetic field changes at a faster rate, the voltage created in the conductor will also increase.