Examples of magnetic mirror in the following topics:
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- In this case, the magnetic force is also perpendicular to the velocity (and the magnetic field vector, of course) at any given moment resulting in circular motion.
- What if the velocity is not perpendicular to the magnetic field?
- If field strength increases in the direction of motion, the field will exert a force to slow the charges (and even reverse their direction), forming a kind of magnetic mirror.
- This force slows the motion along the field line and here reverses it, forming a "magnetic mirror. "
- (Recall that the Earth's north magnetic pole is really a south pole in terms of a bar magnet. )
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- The main idea is that a charge particle can cross a shock and turned around by the tangled magnetic field and recross the shock.
- For argument's sake, let's first focus on the mirror on the left and consider that the mirror on the right is moving.
- Now let's focus on the mirror on the right and consider that the mirror on the left is moving.
- The particle bounces off of the mirror.
- The particle bounces off of the mirror.
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- Ferromagnetism is the property of certain materials that enables them to form magnets and be attracted to magnets.
- Ferromagnetism is the basic mechanism by which certain materials (such as iron) form permanent magnets, or are attracted to magnets.
- Each atom acts like a tiny bar magnet.
- Permanent magnets (materials that can be magnetized by an external magnetic field and remain magnetized after the external field is removed) are ferromagnetic, as are other materials that are noticeably attracted to them.
- Not only do ferromagnetic materials respond strongly to magnets (the way iron is attracted to magnets), they can also be magnetized themselves—that is, they can be induced to be magnetic or made into permanent magnets.
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- When you place an object in front of a mirror, you see the same object in the mirror.
- This section will cover spherical mirrors.
- In a concave mirror, the principal axis is a line that is perpendicular to the center of the mirror.
- In convex mirrors, the principal axis is the same as in a plane or concave mirror, perpendicular to the center of the mirror.
- The focal point is the same distance from the mirror as in a concave mirror.
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- Permanent magnets are objects made from ferromagnetic material that produce a persistent magnetic field.
- Recall that a magnet is a material or object that generates a magnetic field.
- A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field .
- Ferromagnetic materials can be divided into magnetically "soft" materials like annealed iron, which can be magnetized but do not tend to stay magnetized, and magnetically "hard" materials, which do.
- An example of a permanent magnet: a "horseshoe magnet" made of alnico, an iron alloy.
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- There are two type of magnets—ferromagnets that can sustain a permanent magnetic field, and electromagnets produced by the flow of current.
- Such magnets are called ferromagnets.
- In the second class of magnets—known as electromagnets—the magnetic field is generated through the use of electric current.
- Not only do ferromagnetic materials respond strongly to magnets (the way iron is attracted to magnets), they can also be magnetized themselves—that is, they can be induced to become magnetic or made into permanent magnets.
- When current produces a magnetic field on a microscopic scale, as illustrated in , the regions within the material called magnetic domainsact like small bar magnets.
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- Paramagnetism is the attraction of material while in a magnetic field, and diamagnetism is the repulsion of magnetic fields.
- Paramagnetism is a form of magnetism whereby the paramagnetic material is only attracted when in the presence of an externally applied magnetic field.
- Paramagnetic materials have a relative magnetic permeability greater or equal to unity (i.e., a positive magnetic susceptibility) and hence are attracted to magnetic fields.
- Unlike ferromagnets, paramagnets do not retain any magnetization in the absence of an externally applied magnetic field, because thermal motion randomizes the spin orientations responsible for magnetism.
- Diamagnetism is the property of an object or material that causes it to create a magnetic field in opposition to an externally applied magnetic field.
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- Magnetic field lines are useful for visually representing the strength and direction of the magnetic field.
- Since magnetic forces act at a distance, we define a magnetic field to represent magnetic forces.
- If magnetic monopoles existed, then magnetic field lines would begin and end on them.
- (A) The magnetic field of a circular current loop is similar to that of a bar magnet.
- Relate the strength of the magnetic field with the density of the magnetic field lines
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- When an electrical wire is exposed to a magnet, the current in that wire will experience a force—the result of a magnet field.
- When an electrical wire is exposed to a magnet, the current in that wire will be affected by a magnetic field.
- The expression for magnetic force on current can be found by summing the magnetic force on each of the many individual charges that comprise the current.
- In this instance, θ represents the angle between the magnetic field and the wire (magnetic force is typically calculated as a cross product).
- Express equation used to calculate the magnetic force for an electrical wire exposed to a magnetic field
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- This changing magnetic flux produces an EMF which then drives a current.
- When a conductor carries a current, a magnetic field surrounding the conductor is produced.
- The resulting magnetic flux is proportional to the current.
- From Eq. 1, the energy stored in the magnetic field created by the solenoid is:
- Energy is "stored" in the magnetic field.