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P7 A) Permanent Magnets
P7 A) Permanent Magnets
Magnets produce magnetics field, which is a region where another magnet or a magnetic material will experience a non-contact force (a force whereby objects do not need to be touching). Magnets have two poles; a north and a south pole. The north pole of a magnet is positively charged, and the south pole of a magnet is negatively charged. The magnetic forces are stronger at the poles of magnets.
We can draw a diagram that shows the magnetic field that is produced by a magnet. Field lines always go from positive to negative. This means that the field lines will go from the north pole and towards the south pole (this will always be the case). When we draw magnetic field line, it is essential that we include arrows on our lines to show where the field lines go. The magnetic field produced by a bar magnet is shown below.
We can draw a diagram that shows the magnetic field that is produced by a magnet. Field lines always go from positive to negative. This means that the field lines will go from the north pole and towards the south pole (this will always be the case). When we draw magnetic field line, it is essential that we include arrows on our lines to show where the field lines go. The magnetic field produced by a bar magnet is shown below.
The closer the lines are on the diagram, the stronger the magnetic field is. The lines are closet together the closer to the magnet you are, which means that the magnetic force is greater the closer to the magnet that you are. The magnetic force decreases as you move further away from the magnet and the diagram shows this because the field lines become further and further apart.
Attraction and Repulsion
Magnets will produce a non-contact force when another magnetic or magnetic material is place in the original magnet’s magnetic field. We are now going to look at what happens when we place a magnetic into the magnetic field of another magnet. There are two different situations that can happen.
Case 1 – Attraction
When we place opposing poles of two magnets together, the magnets will be attracted to one another. Below is a diagram of the field lines for opposite poles of magnets being attracted to one another.
Magnets will produce a non-contact force when another magnetic or magnetic material is place in the original magnet’s magnetic field. We are now going to look at what happens when we place a magnetic into the magnetic field of another magnet. There are two different situations that can happen.
Case 1 – Attraction
When we place opposing poles of two magnets together, the magnets will be attracted to one another. Below is a diagram of the field lines for opposite poles of magnets being attracted to one another.
Firstly, from the diagram, we can see that the field lines go from north (positive) to south (negative). We can also see that there is a uniform field created between the north and south pole on the flat ends of the magnets; a uniform magnetic field is where the fields lines are straight, parallel and the same distances apart from each other. We can see from the diagram that this is a uniform field because the field lines are straight, parallel and the same distances apart from each other along the straight parts of the magnets (we show a uniform magnetic field by drawing at least 3 lines that are straight, parallel and the same distances apart from one another).
Case 2 – Repulsion
When we place the same poles of two magnets, the magnets will repel one another. This can happen when we place two north poles next to one another, or two south poles next to one another. The field lines for north-north repulsion are shown below.
Case 2 – Repulsion
When we place the same poles of two magnets, the magnets will repel one another. This can happen when we place two north poles next to one another, or two south poles next to one another. The field lines for north-north repulsion are shown below.
The field lines for south-south repulsion are shown below.
The only difference between the two diagrams is the direction of the arrows. For the north-north diagram, the arrows on the field lines are going away from the north poles (remember, field lines always go away from the north/ positive pole). For the south-south diagram, the arrows on the field lines are going towards the south poles (remember, field lines always go towards the south/ negative pole).
Drawing Magnetic Field Diagrams
We can prove that the magnetic field produced by a magnetic looks like it does at the start by using a compass. A compass has a needle that is a bar magnetic. The needle is very small and light weight, which is why it is able to easily move. A compass will always line up to the strongest magnetic field. When there is no other magnetic fields present, a compass will always point north because of the magnetic field produced by the north and south poles on earth.
However, when we place a compass next to a magnet, which will exert a stronger magnetic force than the poles of the earth, we will see that the needle of the compass will line up with the magnetic field produced by the bar magnet rather than the magnetic field of the earth. We can place a compass around the magnet and trace the magnetic field lines that the magnet produces. The outcome of this experiment is shown below.
We can prove that the magnetic field produced by a magnetic looks like it does at the start by using a compass. A compass has a needle that is a bar magnetic. The needle is very small and light weight, which is why it is able to easily move. A compass will always line up to the strongest magnetic field. When there is no other magnetic fields present, a compass will always point north because of the magnetic field produced by the north and south poles on earth.
However, when we place a compass next to a magnet, which will exert a stronger magnetic force than the poles of the earth, we will see that the needle of the compass will line up with the magnetic field produced by the bar magnet rather than the magnetic field of the earth. We can place a compass around the magnet and trace the magnetic field lines that the magnet produces. The outcome of this experiment is shown below.
Here is a little bit information as to how we get the above outcome. The first step is to place the magnet onto a piece of paper and draw around where the magnet is. We then place the compass near the magnet. The needle of the compass will line up with the magnetic field produced by the magnet. We then mark on the paper the direction of the needle. We then move the compass along the magnetic field line and tracing the field lines around the magnet. We keep moving the compass and join up all of the points where the compass was.
After we have completed one line going from the north pole of the magnet to the south pole of the magnet, we place the compass in a new location and repeat the process again. This will show us the different magnetic field lines. After we have completed a few field lines, we should get a diagram that looks like what is shown above.
After we have completed one line going from the north pole of the magnet to the south pole of the magnet, we place the compass in a new location and repeat the process again. This will show us the different magnetic field lines. After we have completed a few field lines, we should get a diagram that looks like what is shown above.