Electromotive force induced in a conducting rod

• DottZakapa
In summary, the induced current in this exercise is counterclockwise because the rod is moving upward, decreasing the magnetic flux and causing the induced current to flow in the same direction as the magnetic field that induced it. This is in accordance with the convention that a cross is into the page and the vector product of velocity and magnetic field points to the left. There is no indication in the solution about the positioning of the red rod in the picture.
DottZakapa
Homework Statement
Two long, parallel and perfectly conducting rails at a distance l = 50 cm from each other are placed in a homogeneous magnetic field with magnetic induction B = 2 mT, which is perpendicular to the rail plane. The rails are conductively connected at one point.
Electrical resistance of the connection is R = 5 Ω. A perfectly conducting rod slides on these rails with a constant speed v = 2 ms-1. Determine:
a) the electromotive force induced in the conducting rod, the value and direction of induced electric current in the closed part of the circuit,
b) the mechanical pulling force needed to keep the rod at the constant speed and mechanical powe
Relevant Equations
electromotive force

i don't understand why in the solution of this exercise, the induced electromotive force / current is counterclockwise.
Shouldn't it be clockwise?
##emf=-\frac {d \Phi_B} {dt} ##
According to the picture the rod is moving upward, the magnetic flux (entering the page) is decreasing due to a reduction of the area, consequently the induced current will flow in such way that the magnetic field produced is in the same direction of the magnetic field that induced it. It would go counterclockwise only if the area was increasing which would imply an increase of magnetic flux, hence the magnetic field produced by the induced current will oppose it.
Isn't it?

I agree with you. The convention is that a cross is into the page (circle with center point is out of the page) and then ##\vec v \times \vec B ## points to the left.

Any indication in the solution (which solution?) that they have the red rod on the top of the picture, having passed the resistor ?

1. What is electromotive force (EMF)?

EMF is the potential difference or voltage generated in a circuit when there is a change in magnetic flux. It is measured in volts.

2. How is EMF induced in a conducting rod?

EMF is induced in a conducting rod when it moves through a magnetic field or when there is a change in the magnetic field passing through it. This change in magnetic field causes a change in the magnetic flux, which in turn generates an EMF.

3. What factors affect the magnitude of EMF induced in a conducting rod?

The magnitude of EMF induced in a conducting rod depends on the strength of the magnetic field, the speed of the rod, and the length of the rod. It also depends on the angle between the direction of motion of the rod and the direction of the magnetic field.

4. How is EMF induced in a conducting rod related to Faraday's law of induction?

Faraday's law of induction states that the magnitude of EMF induced in a circuit is directly proportional to the rate of change of magnetic flux passing through the circuit. In the case of a conducting rod, the change in magnetic flux causes an EMF to be induced in the rod.

5. What are some real-world applications of EMF induced in a conducting rod?

EMF induced in a conducting rod is the principle behind the functioning of electric generators, which convert mechanical energy into electrical energy. It is also used in devices such as induction cooktops and magnetic levitation trains.

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