Heat generated due to motion of wire in magnetic field

In summary, the question asks whether thermal energy will be generated in a wire that is moving perpendicularly to a magnetic field, given that the wire has a resistance R. The first explanation states that due to induced EMF and current flow, heat energy will be generated. However, the second explanation argues that since current only flows in closed loops and there is a period of no current, no heat energy will be generated. The correct answer is that there will be a very small amount of heat energy generated, but it is negligible in high school physics.
  • #1
Titan97
Gold Member
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Homework Statement


A wire is moved with constant velocity such that the motion is perpendicular to the length of the wire in a region containing magnetic field perpendicular to the plane of motion. The wire has a resistance R. Will thermel energy be generated in the wire?

Homework Equations


##V=BLv##

The Attempt at a Solution


Due to induced EMF, positive charges accumulate on one end and negative charge accumulated on the other end. Since the process involves motion of charges (current), then heat energy will be generated.

But in an alternative explanation, current flows only in closed loops. So according to ##P=i^2R##, since ##i=0##, heat energy will not be generated. Which answer is correct?
 
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  • #2
I think you have answered it in the first answer, since combining it with the second one there will be a short period during which there will be charge (electrons) motioning towards the one end of the wire. That is the electrons will collide with some of the atoms as they move towards the one end of the wire.
 
Last edited:
  • #3
But according to the given answer given, no heat energy is produced.
 
  • #4
Titan97 said:
But in an alternative explanation, current flows only in closed loops. So according to P=i2RP=i2RP=i^2R, since i=0i=0i=0, heat energy will not be generated. Which answer is correct?
That is true. The movement of charges takes place for a very short time, which is negligibly small. So, as far as high school physics is concerned, I believe the answer given is correct.
 

1. What is the principle behind the generation of heat due to motion of a wire in a magnetic field?

The principle behind the generation of heat due to motion of a wire in a magnetic field is known as electromagnetic induction. This occurs when a conductor, such as a wire, moves through a magnetic field, creating a flow of electrons. This flow of electrons causes resistance, which in turn produces heat.

2. How does the speed of the wire affect the amount of heat generated?

The speed of the wire moving through the magnetic field directly affects the amount of heat generated. The faster the wire moves, the more electrons are forced to move, creating a higher flow of current and thus, more heat. Therefore, the heat generated is directly proportional to the speed of the wire.

3. Can the direction of the wire's motion affect the heat generated?

Yes, the direction of the wire's motion can affect the heat generated. If the wire is moving perpendicular to the magnetic field, it will produce the maximum amount of heat. However, if the wire is moving parallel to the magnetic field, no heat will be generated as there is no change in the magnetic flux.

4. How does the strength of the magnetic field impact the amount of heat generated?

The strength of the magnetic field also directly affects the amount of heat generated. The stronger the magnetic field, the more force will be applied to the electrons in the wire, resulting in a higher flow of current and thus, more heat. Therefore, the heat generated is directly proportional to the strength of the magnetic field.

5. Can the length and thickness of the wire affect the amount of heat generated?

Yes, the length and thickness of the wire can affect the amount of heat generated. A longer wire will have more resistance and therefore, more heat will be generated. Similarly, a thicker wire will have less resistance and thus, less heat will be generated. Therefore, the heat generated is inversely proportional to the length and thickness of the wire.

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