# Induced EMF from moving conducting rod

• OhBoy
In summary: This means that the induced current will not significantly affect the direction of the force on the rod, and the force will mainly come from the original external magnetic field. In summary, the force that resists the movement of the conducting rod on the horizontal rails is mainly derived from the external magnetic field directed into the page.
OhBoy

## Homework Statement

Lets say we have two horizontal rails connected by a resistor to the left, and we have a movable conducting rod that slides without friction on the rails.There is a uniform magnetic field going into the page.

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## The Attempt at a Solution

Now, I know that if the rail moves to the right with a velocity v, then Hall's effect shows that there will be an induced emf, and the resistor will draw a current. Now there should be a resisting force to stop the rod from moving but I'm not sure where the force comes from. If there is a current going counter clockwise, the current through the bridge will provide its own magnetic field going out of the page. Now, going back to the rod, current is moving up, field from bridge out of the screen, that makes the force going towards the right, not the left to resist the velocity. Do I use the field into the pay because it will (always?) be stronger than one produced by current through resistor? That would make the force to the left. I just want to make sure I have a conceptual understanding of where this force comes from.

So what am I doing wrong? Where is the resisting force derived when a force goes into move the conducting rod?

Last edited:
OhBoy said:
Do I use the field into the pay [page] because it will (always?) be stronger than one produced by current through resistor? That would make the force to the left. I just want to make sure I have a conceptual understanding of where this force comes from.

Yes, in this situation it is generally assumed that the field produced by the induced current is negligible compared to the fixed external field (directed into the page).

OhBoy

## 1. What is induced EMF from a moving conducting rod?

Induced EMF from a moving conducting rod refers to the phenomenon where a changing magnetic field induces an electric field in a conductor, leading to the generation of an electromotive force (EMF) or voltage across the conductor. This is also known as electromagnetic induction.

## 2. How is induced EMF from a moving conducting rod calculated?

The induced EMF in a conducting rod can be calculated using Faraday's Law, which states that the magnitude of the induced EMF is equal to the rate of change of magnetic flux through the conductor. It can be expressed as E = -N(dΦ/dt), where E is the induced EMF, N is the number of turns in the conductor, and dΦ/dt is the rate of change of magnetic flux.

## 3. What factors affect the magnitude of induced EMF from a moving conducting rod?

The magnitude of induced EMF from a moving conducting rod depends on several factors, including the strength of the magnetic field, the speed of the conductor, the angle between the magnetic field and the conductor, and the length and orientation of the conductor in the magnetic field.

## 4. How is induced EMF from a moving conducting rod used in practical applications?

Induced EMF from a moving conducting rod has many practical applications, such as in generators, transformers, and motors. It is also used in devices like induction cooktops and wireless charging systems. In these applications, the induced EMF is used to produce electrical energy from mechanical energy or vice versa.

## 5. What is the difference between induced EMF from a moving conducting rod and self-induced EMF?

The difference between induced EMF from a moving conducting rod and self-induced EMF lies in the source of the changing magnetic field. In induced EMF, the changing magnetic field is produced by an external source, while in self-induced EMF, the changing magnetic field is produced by the current flowing through the conductor itself. Additionally, induced EMF is typically larger in magnitude compared to self-induced EMF.

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