A cross product for two vectors can be determined as. Two north poles repel one another, and two south poles will also repel one another just like how like electric charges repel one another and opposite charges attract each other. The magnetic compass needle of a compass moves with a torque, the rotational force of a body in motion. You can calculate this torque using a cross product of the rotational force, torque, as the result of the magnetic moment with the magnetic field.
If you determine how much of the magnetic force is due to rotation for an object in a magnetic field, that value is the torque. You can determine either the magnetic moment or the force of the magnetic field. Because a compass needle aligns itself with the Earth's magnetic field, it will point north because aligning itself this way is its lowest energy state.
It's the compass at rest after all other forces that move the compass around have been accounted for. You can determine strength of this rotational motion using torque. A magnetic field causes matter to show magnetic properties, especially among elements such as cobalt and iron which have unpaired electrons that let charges move and magnetic fields emerge.
Magnets that are either classified as paramagnetic or diamagnetic let you determine whether a magnetic force is attractive or repulsive by the magnet's poles. Diamagnets have no or few unpaired electrons and can't let charges flow freely so easily as other materials do. They are repelled by magnetic fields. Paramagnets have unpaired electrons to let charge flow and are, therefore, attracted to magnetic fields.
To determine whether a material is diamagnetic or paramagnetic, determine how electrons occupy orbitals based on their energy with respect to the rest of the atom. Make sure electrons must occupy every orbital with only one electron before the orbitals have two electrons.
If you end up with unpaired electrons, as is the case with oxygen O 2 , the material is paramagnetic. Otherwise, it is diamagnetic, like N 2. You can imagine this attractive or repulsive force as the interaction of one magnetic dipole with the other.
The potential energy of a dipole in an external magnetic field is given by the dot product between the magnetic moment and the magnetic field. This potential energy is. The dot product measures the scalar sum resulting from multiplying the x components of one vector to the x components of another while doing the same for y components. The minus sign in the equation for potential energy indicates that potential is defined as negative for higher potential energies of magnetic force.
After studying physics and philosophy as an undergraduate at Indiana University-Bloomington, he worked as a scientist at the National Institutes of Health for two years. He primarily performs research in and write about neuroscience and philosophy, however, his interests span ethics, policy, and other areas relevant to science. What Makes Magnets Repel? What Is a Magnetometer? The rule is: wherever there is stored-up energy in an object and the object is not tied down or stuck in place , then the object will be pushed in the direction that causes the stored-up energy to decrease.
The stored-up energy will be reduced and replaced by movement energy. So if two magnets are pointing with unlike-poles together north pole to a south pole , then bringing them closer together decreases the energy stored up in the magnetic field.
They will be pushed in the direction that decreases the amount of stored-up energy. That is, they are forced together this is called attraction. If two magnets are pointing with like-poles together a south pole to a south pole OR north to north , then stored-up energy will decrease if they move apart.
So our rule says the magnets will be pushed in the direction that decreases the amount of stored-up energy. That is, they are forced apart repelled. Earth is also surrounded by a gravitational field which also contains stored up energy. Unlike magnetism, gravity never repels because gravity only points one way.
There are no north and south poles for gravity. Read more: Earth's magnetic heartbeat, a thinner past and new alien worlds. The energy needed to pull the magnets apart comes from you, and you get it from the food you eat.
And the plants or animals you eat get their energy from other plants and animals, or from the Sun. To become magnetize d, another strongly magnetic substance must enter the magnetic field of an existing magnet.
The magnetic field is the area around a magnet that has magnetic force. All magnets have north and south poles. Opposite poles are attracted to each other, while the same poles repel each other. When you rub a piece of iron along a magnet, the north-seeking poles of the atoms in the iron line up in the same direction.
The force generated by the align ed atoms creates a magnetic field. The piece of iron has become a magnet. Some substances can be magnetized by an electric current. When electricity runs through a coil of wire, it produces a magnetic field.
The field around the coil will disappear, however, as soon as the electric current is turned off. Geomagnetic Poles. The Earth is a magnet. The geomagnetic pole s are not the same as the North and South Poles. Strangely, the magnetic records of rocks formed at the same time seem to point to different locations for the poles. Thus, the plates on which the rocks solidified have moved since the rocks recorded the position of the geomagnetic poles. These magnetic records also show that the geomagnetic poles have reversed—changed into the opposite kind of pole—hundreds of times since the Earth formed.
Therefore, it can be a useful tool for helping people find their way around. The north end of a magnet points toward the magnetic north pole.
Solar wind , charged particles from the sun, presses the magnetosphere against the Earth on the side facing the sun and stretches it into a teardrop shape on the shadow side. The magnetosphere protects the Earth from most of the particles, but some leak through it and become trapped. When particles from the solar wind hit atoms of gas in the upper atmosphere around the geomagnetic poles, they produce light displays called aurora s. Historic Directions The ancient Greeks and Chinese knew about naturally magnetic stones called "lodestones.
The Chinese discovered that they could make a needle magnetic by stroking it against a lodestone, and that the needle would point north-south. Animal Magnetism Some animals, such as pigeons, bees, and salmon, can detect the Earth's magnetic field and use it to navigate. Scientists aren't sure how they do this, but these creatures seem to have magnetic material in their bodies that acts like a compass.
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