Magnetic field around a wire

In summary: So in summary, the direction of the magnetic field around a wire with current is determined by the right hand rule, with the flux lines pointing towards north. However, a single wire does not have north or south poles, unlike a normal magnet. You need a solenoid to define poles.
  • #1
johann1301
217
1
How do you place/define north and south in the magnetic field around a wire with a current running through it?
 
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  • #3
You can use the right hand rule: http://en.wikipedia.org/wiki/Right_hand_grip_rule#Direction_associated_with_a_rotation

An electric current passes through a straight wire. Here, the thumb points in the direction of the conventional current (from positive to negative), and the fingers point in the direction of the magnetic lines of flux.

The direction of the flux lines points towards north. Note that a single wire has a magnetic field running around it, not through it like a normal magnet. As such, there is no single north or south pole.
 
  • #4
Drakkith said:
The direction of the flux lines points towards north. Note that a single wire has a magnetic field running around it, not through it like a normal magnet. As such, there is no single north or south pole.

The second statement above contradicts the first. How can the flux lines point towards north when there is no north or south pole?

The first statement is actually incorrect. there is no such thing as a north pole or a south pole for the magnetic field of a single wire. You need a solenoid in order to be able to define poles.
 
  • #5


The direction of the magnetic field around a wire with a current running through it can be determined using the right-hand rule. If the wire is held in the right hand with the thumb pointing in the direction of the current, the fingers will curl around the wire in the direction of the magnetic field. This means that the north pole of the magnetic field will be in the direction of the curled fingers, and the south pole will be in the opposite direction.

Alternatively, the direction of the magnetic field can also be determined by using a compass. If the compass is placed near the wire, the north pole of the compass needle will point towards the south pole of the magnetic field and vice versa. This can be used to define the north and south poles of the magnetic field around the wire.

It is important to note that the direction of the magnetic field around a wire is circular, with the strength of the field decreasing as you move further away from the wire. Additionally, the direction of the field will reverse if the direction of the current is reversed. Overall, the direction of the magnetic field around a wire can be easily determined and defined using the right-hand rule or a compass, providing a clear understanding of the north and south poles in the magnetic field.
 

1. What is a magnetic field?

A magnetic field is a region in space where a magnetic force can be detected. It is created by moving electric charges, such as electrons, and is characterized by its direction and strength.

2. How is a magnetic field created around a wire?

A magnetic field is created around a wire when an electric current flows through it. The direction of the magnetic field is determined by the direction of the current, with the field forming circular patterns around the wire.

3. What is the relationship between the strength of the magnetic field and the current in the wire?

The strength of the magnetic field around a wire is directly proportional to the current running through the wire. This means that the larger the current, the stronger the magnetic field will be.

4. What factors can affect the strength of the magnetic field around a wire?

The strength of the magnetic field can be affected by the distance from the wire, the magnitude of the current, and the material of the wire. The closer the object is to the wire and the larger the current, the stronger the magnetic field will be. Different materials can also have different effects on the strength of the magnetic field.

5. How can the direction of the magnetic field around a wire be determined?

The direction of the magnetic field around a wire can be determined using the right-hand rule. This rule states that if you point your right thumb in the direction of the current, your fingers will curl in the direction of the magnetic field. Alternatively, a compass can be used to determine the direction of the magnetic field as it will align with the field lines.

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