The light is produced by radiation from solar storms.

Magnetic poles interact with each other.

Define ferromagnet.

Magnetic fields and magnetic field lines can be defined.

The effects of magnetic fields on moving charges are discussed.

The direction of the magnetic force on a moving charge can be determined by using the right hand rule.

The magnetic force on a charge is calculated.

There are examples and applications for the effects of a magnetic field on a moving charge.

The path of a charge is moving in a magnetic field.

Torque on a current loop can be described in terms of motor and meter Torque on a current loop can be described in terms of meter and motor Torque on a current loop can be described in terms of meter and motor

Ampere's Law states that currents can produce a magnetic field.

The right hand rule 2 can be used to determine the direction of magnetic field loops.

The Aurora Borealis can be seen through the kitchen window. The spectacle is shaped by the force that holds the note to the fridge.

People have been aware of magnetism for thousands of years. Magnesia is a region of Asia Minor that dates to before the time of Christ.

Magnetic rocks found in Magnesia stimulated interest during ancient times. Magnets were used as navigation compasses. The use of magnets in compasses resulted in improved long-distance sailing, as well as in the names of "North" and "South" being given to the two types of magnetic poles.

magnetism is important in our lives. Physicists' understanding of magnetism has allowed the development of new technologies. Without the applications of magnetism and electricity on a small scale, the iPod wouldn't have been possible.

One of the first large successes of nanotechnology was the discovery that weak changes in a magnetic field in a thin film of iron and chromium could cause much larger changes in electrical resistance. The discovery of giant magnetoresistance and its applications to computer memory was made by Albert Fert from France and Peter Grunberg from Germany.

Magnets are found in all electric motors with uses as diverse as starting cars and moving elevators.

Magnetic fields can be used in generators to produce hydroelectric power or bicycle lights. Magnets are used to separate iron from other refuse. Hundreds of millions of dollars are spent each year on magnetic containment of fusion as a future energy source. Magnetic resonance imager (MRI) has become an important diagnostic tool in the field of medicine, and the use of magnetism to explore brain activity is a subject of contemporary research and development. Computer hard drives, tape recording, and levitation of high-speed trains are some of the applications on the list. The Van Allen belts have charged particles trapped in them.

All of these phenomena are linked by a small number of underlying physical principles.

iPods would not be possible without a deep understanding of magnetism.

There are different shapes, sizes, and strengths of magnets. All of them have a north and a south pole. A monopole is not an isolated pole.

Iron can be attracted by magnets in a refrigerator door. Magnets can attract or repel other magnets.

Experiments show that magnets have two poles. One pole will point to the north if it is freely suspended.

It is a universal characteristic of all magnets that repel poles.

It is not possible to separate the north and south poles in the way that + and - charges can be separated.

There is a thread that points toward the north. The two poles of the magnet are labeled N and S.

The magnetic pole that is near the North Pole has been wrongly referred to as the "North Pole". The north magnetic pole should be called the south magnetic pole.

Unlike poles, poles repel.

The poles of the north and south are always in pairs. More pairs of poles result from attempts to separate them. We will eventually get down to an iron atom with a north pole and a south pole if we continue to split the magnet.

Sunspots occur in pairs of north and south magnetic poles all the way down to the very small scale. Many types of particles, such as electrons, protons, and neutrons, have both a north and a south pole.

Magnetic poles repel and 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- If you can show it to the two fridge magnets, that's great.

A group of materials made from the rare earth elements are used to make magnets. Weak magnetic effects are only visible with sensitive instruments.

An unmagnetized piece of iron is placed between two magnets and either cooled or tapped. The north pole of the original magnet is adjacent to the south pole of the iron, which becomes a permanent magnet. There are attractive forces between the magnets.

The poles of individual atoms are aligned.

A ferromagnetic object has small and randomly oriented domains. If the material is heated and cooled, or tapped in the presence of other magnets, it can be made permanent.

Each atom is a tiny bar magnet.

Hard blows can be used to demagnetize a permanent magnet.

The orientation and size of the domains can be randomized by increased thermal motion. The temperature for iron is well above the room temperature. There are elements that are ferromagnetic only below room temperature.

Magnetic effects were discovered early in the 19th century. The first significant observation was made by Hans Christian Oersted, a scientist from the Danes. The movement of charges had a connection with magnets.

The device uses a magnetic field. The patient is on the gurney.

Figure 22.10 shows the response of iron to a coil and a permanent bar magnet.

The basic characteristics of electromagnets and ferromagnets are the same, for example, they have north and south poles that can't be separated.

The shape of the fields can be seen by looking at the iron filings near the coil and magnet.

Their response to a current-carrying coil and a permanent magnet is seen to be very similar, especially near the ends of the coil and the magnet.

Strong magnetic effects can be produced by combining a ferromagnet with an electromagnet. Strong magnetic effects, such as lifting scrap metal, are enhanced by ferromagnetic materials. Limits to how strong the magnets can be made are imposed by coil resistance, and so superconducting magnets may be used. Superconductivity is destroyed by a magnetic field.

Strong magnetic effects can be produced by an electromagnet with a ferromagnetic core. The poles of the electromagnet are aligned with the domains in the core.

There are a few uses of electromagnets and ferromagnets. The orientation of the magnetic fields of small domains can be reversed or erased with ferromagnetic materials. Magnetic information storage is one of the most common applications. Our digital world depends on this property.

A ferromagnetic material is coated with a floppy disk. The information stored here is either digital or magnetic and can be used in a variety of applications.

An electric current creates magnetism. The strength and direction of magnetic fields created by various currents are explored in later sections. Currents that are associated with particles like protons allow us to explain ferromagnetism.

The fact that it is impossible to separate the north and south magnetic poles is important to the statement that electric current is the source of magnetism. A magnetic field that acts like a north and south pole pair is produced by a current loop.

If magnetic monopoles existed, we would have to modify the connection between magnetism and electrical current. Magnetic monopoles are simply never observed and so searches at the subnuclear level continue. We would like to see evidence of them if they exist.

The source of magnetism is electric current.

The image of a spinning electron is not in line with modern physics. They give a useful way of understanding phenomena.

Einstein is said to have been fascinated by a compass when he was a child. His ability to think deeply and clearly about action at a distance enabled him to create his revolutionary theory of relativity.

A magnetic field line is a direction that a small compass points at. The strength of the field is determined by the density of the lines.

A magnetic field will not be disturbed by small compasses. A small compass that is placed in these fields will align itself with the field line at its location, with the north pole pointing in the direction of B. There are symbols used for field into and out of the paper.

The fields shown here could be mapped with small compasses. The symbols used for the field pointing inward and outward are similar to the symbols used for the tip of an arrow.

A field is a way of mapping forces surrounding an object that can act on another object at a distance. The object is represented by the field. Magnetic forces, electrical forces, and electric forces are mapped.

There are a number of hard-and-fast rules. Magnetic field lines are not a physical entity in and of themselves and are used to represent the field.

At any point in space, the direction of the magnetic field is related to the field line. The direction of the field line will be pointed out by a small compass.

The field's strength is determined by how close the lines are. The areal density is proportional to the number of lines per unit area.

Magnetic field lines can't cross at any point in space.

Closed loops are formed by continuous magnetic field lines. They go from the north to the south.

The north and south poles cannot be separated. Electric field lines begin and end on positive and negative charges. Magnetic field lines would begin and end on magnetic monopoles.

The answer is related to the fact that magnetism is caused by the flow of charge. Magnetic fields exert force on other magnets that have moving charges.

The magnetic force on a moving charge is one of the most fundamental.

The magnetic force is more complex than the simple Coulomb force because of the number of factors that affect it.

The force on a charged particle moving in a magnetic field is how we define magnetic field strength. The tesla relates to other SI units.

The strongest magnets have fields of 2 T or more. The Earth's magnetic field is very small.

To determine the direction of the magnetic force on a positive moving charge, you have to point the thumb of the right hand at the direction of the fingers on the palm. One way to remember is that there is one velocity and the thumb represents it. The fingers represent the field lines. You would push the force with your palm. The force on a negative charge is the opposite of the force on a positive charge.

Magnetic fields exert force on moving objects. One of the most basic forces is this force. The direction of the magnetic force on a moving charge is related to the plane formed by it and follows the right hand rule-1. The magnitude of the force is determined by the angle between and and.

There is no force on static charges. There is a force on moving charges.

Magnetic fields are created when charges move. The electric and magnetic fields affect each other when there is relative motion.

The Earth's small magnetic field makes it hard to see or experience forces. If you put a 20-nC positive charge on a glass rod in a physics lab, you can demonstrate this.

A positively charged object moving due west in a region where the Earth's magnetic field is due north experiences a force that is straight down as shown. A negative charge moving in the same direction would feel a force.

The magnetic field strength and direction is given to us. The equation can be used to find the force.

The angle between the velocity and the direction of the field is what we see.

This force is not significant on any object. The effects of the Earth's magnetic field are very important.

Magnetic force can cause a particle to move. Some of the Cosmic rays that approach the Earth are energetic charged particles. The Earth's magnetic field can force them into spirals. Magnetic force keeps the particles in a circular path. The basis of a number of phenomena can be found in the curved paths of charged particles.

The artist's depiction of a bubble chamber has high-energy charged particles moving through the liquid hydrogen. The curved paths of the particles are caused by a strong magnetic field. The mass, charge, and energy of the particle can be found by using the radius of the path.

Magnetic force doesn't work on the charged particle because it's always perpendicular to velocity. The particle's speed and energy remain the same. The direction of motion is not affected. This is typical of circular motion. The centripetal force is supplied by the magnetic force.

There are small circles with x's--like the tails of arrows--represented by a negatively charged particle moving in the plane of the page. The magnetic force is the same as the velocity, but it is not magnitude.

The radius of the path of a charged particle with mass and charge is moving at a speed that is close to a magnetic field of strength. The component of the velocity that is perpendicular to the field is called the velocity component. Since the magnetic force is zero for motion parallel to the field, the component of the velocity parallel to the field is unaffected. This produces a spiral motion.

To demonstrate this, use a magnetic field of strength equal to the speed of sound to calculate the radius of the path of an electron.

The side view shows what happens when a computer monitor or TV screen has a magnet in it. The component of their velocity is parallel to the field lines as they move toward the screen. The image on the screen is distorted.

Since all other quantities in the equation are known, we can find the radius of curvature directly from the equation.

A large effect is indicated by the small radius. The electrons in the TV picture tube are made to move in very tight circles.

The figure shows how electrons don't follow the magnetic field lines. The charges spiral along the field lines because the component of velocity parallel to the lines is unaffected. A kind of magnetic mirror can be formed if field strength increases in the direction of motion.

When a charged particle moves along a magnetic field line into a region where the field becomes stronger, the particle experiences a force that reduces the component of velocity parallel to the field.

The properties of charged particles in magnetic fields are related to other things. As seen above, charged particles approaching magnetic field lines may get trapped in spirals rather than crossing them. Cosmic rays follow the Earth's magnetic field lines and enter the atmosphere near the magnetic poles, causing the southern or northern lights to illuminate. The particles that approach the middle latitudes must cross magnetic field lines. Cosmic rays give a higher radiation dose at the poles than at the equator.

Cosmic rays from the Sun and deep outer space do not cross the Earth's magnetic field lines.

The Van Allen radiation belts are formed by charged particles trapped in the Earth's magnetic field.

In the few minutes it took lunar missions to cross the Van Allen radiation belts, astronauts received radiation doses more than twice the allowed annual exposure for radiation workers. Jupiter has strong magnetic fields and is one of the planets with similar belts.

The Earth's magnetic field traps energetic charged particles in the Van Allen radiation belts.

One belt is about 300 km above the Earth's surface, the other 16,000 km. The charged particles in these belts migrate along magnetic field lines and are reflected away from the poles by the stronger fields there. The Sun and sources in outer space replenish the charged particles that enter the atmosphere.

Magnetic fields can be used to contain charged particles. The giant particle accelerators have been used to explore the substructure of matter. Magnetic fields can be used to control the direction of the charged particles, as well as to focus them into beams and overcome the repulsion of like charges in these beams.

The most powerful particle accelerator in the world until 2008 is located in Illinois and uses magnetic fields to direct its beam. This and other accelerators have been in use for a long time and have allowed us to understand some of the laws. One of the most promising devices is the tokamak, which uses magnetic fields to trap and direct the charged particles. The microwaves are sent into the oven.

Nuclear fusion is being studied with the goal of economical production of energy by tokamaks. The device has magnetic fields that direct the charged particles.

Many mass spectrometers use magnetic fields to measure mass. Mass information can be obtained by measuring the path of a charged particle in the field. Mass spectrometers and gas chromatographs are used to determine the make-up of large biological molecules.

The effects of a magnetic field on free- moving charges have been seen. The conductor's charges are affected by the magnetic field.

The Hall effect has important implications.

The figure shows what happens when charges move through a conductor. The field is related to the width of the conductor. The conventional current is to the right in both parts of the figure.

The electrons move to the left. Positive charges move the current to the right.

electrons feel a magnetic force towards one side of the conductor, leaving a net positive charge on the other side

The Hall emf is caused by the magnetic field that is out of the page, represented by circled dots. The Hall effect can be used to determine the sign of the charge carriers if the direction of the field is known.

The Hall effect can be used to determine whether positive or negative charges carry the current. The Hall effect shows that electrons carry current in metals and that positive charges carry current in some electronics. The Hall effect is used to investigate the movement of charges and their densities in materials. The Hall effect is an example of quantum behavior.

Blood flow rate is one of the uses of the Hall effect. We need an expression for the Hall emf across a conductor to examine these quantitatively. The magnetic force can move negative charges to one side, but they can't build up without a limit. The electric field caused by their separation grows to equal the magnetic force.

The electric field is uniform across the conductor, as is the magnetic field. The Hall emf is the relationship between the electric field and the voltage.

Where is the Hall effect voltage across a conductor of width through which charges move at a speed?

The Hall emf balances the magnetic force on moving charges with an electric force. The equilibrium is quickly reached when charge separation builds up until it is balanced by the electric force.

Magnetic field strength is one of the most common uses of the Hall effect. Hall probes can be made very small, allowing fine position mapping. Carefully calibrating hall probes can make them very accurate. The Hall effect can be used to measure fluid flow in fluid with no charges. The Hall emf is produced by a magnetic field applied to the flow direction. The magnitude of the Hall emf is what the pipe diameter is, so that the average velocity can be determined.

The Hall effect can be used to measure fluid flow. The Hall emf is proportional to the average velocity and is measured across the tube.

A Hall effect flow probe is placed on an arteries and applied with a 0.100-T magnetic field.

The equation can be used to find.

This is the average output. The instantaneous voltage changes with the blood flow. The measurement has a small voltage. The Hall emf is AC with the same frequencies if an AC magnetic field is applied. An amplifier can pick out the right frequencies, eliminating signals and noise from other frequencies.

Magnetic force on charges moving in a conductor is transmitted to the conductor itself.

The same direction as that on the individual moving charges is given by the right hand rule 1 when the magnetic field exerts a force on a current-carrying wire. The force can be large enough to move the wire because of the large number of moving charges.

Taking a sum of the magnetic forces on individual charges can be used to derive an expression for the magnetic force on a current.

The force on an individual charge is given. Taking to be uniform over a length of wire and zero elsewhere, the total magnetic force on the wire is then, where is the number of charge carriers in the section of wire of length.

The force on the wire is determined by where the cross-sectional area of the wire is.

22.16 is the equation for magnetic force on a length of wire carrying a current in a uniform magnetic field.

The direction of this force is given by RHR-1, with the thumb in the direction of the current.

RHR-1 gives its direction.

A large magnetic field creates a force on a small length of wire.

Magnetic force on current-carrying conductors converts electric energy to work. Magnetic force pumps fluids without moving mechanical parts is a clever application.

The magnetic force on the current can be used as a non mechanical pump.

A strong magnetic field is applied across a tube and a current is passed through the fluid at right angles to the field, resulting in a force on the fluid parallel to the tube axis as shown. The absence of moving parts makes it attractive to move a hot substance in a nuclear reactor. Experimental artificial hearts are testing out this technique for pumping blood, possibly circumventing the adverse effects of mechanical pumps.

Nuclear submarines have the ability to hide and survive a first or second nuclear strike. Development work is needed for existing MHD drives.

The MHD system in a nuclear submarine would allow it to run more silently and produce less turbulence than propellers. The Hunt for Red October dramatized the development of a silent drive submarine.

There are loops of wire in the magnetic field. The magnetic field exerts Torque on the loops when current is passed through them. The mechanical work is done with electrical energy.

A loop of wire attached to a rotating shaft feels magnetic forces that produce a clockwise Torque as seen from above.

The magnetic field is uniform over the rectangular loop. The forces on the top and bottom segments are parallel to the shaft, so there is no Torque. There is no net force on the loop because the vertical forces are equal in magnitude and opposite in direction. Torque is defined as where the force is applied, the distance from the pivot that the force is applied, and the angle between and.

The clockwise Torque is produced by each force. The two add to give a total Torque, since the Torque on each vertical segment is.

The angle between and the field is the same as the angle between and the loop.

The force on each segment is determined by the length of the segment.

We get times the Torque of one loop if we have a multiple loop of turns.

There is a magnetic field and a current-carrying loop. The equation can be used for a loop of any shape. The loop carries a current, has turns, each of the area, and the loop makes an angle with the field. The loop has zero net force.

The maximum Torque can be found on a 100 turn square loop of a wire with a side carrying 15.0 A of current.

Torque can be found using the loop.

It's large enough to be useful in a motor.

The maximum is what was found in the preceding example. The coil's Torque decreases to zero as it rotates. Once the coil rotates past, the Torque reverses its direction. Unless we do something, the coil will move back and forth about equilibrium. We can reverse the current with brushes if we want the coil to continue rotating in the same direction.

The figure's meter has magnets shaped to limit the effect of the loop over a large range. The Torque is proportional to something. A linear spring balances the current produced Torque. The needle is proportional to. The gauge reading can be adjusted if an exact proportionality cannot be achieved. We use a large loop area, high magnetic field, and low-resistance coil to make a galvanometer for use in ammeters that have a low resistance and respond to small currents.

Meters are very similar to a motor, but only move through a part of a revolution. The magnetic poles of this meter are shaped so that the component of the loop constant is not dependent on the current.

Magnetic fields created by overhead electric power lines can interfere with compass readings. When Oersted discovered that a current in a wire affected a compass needle, he was not dealing with large currents. The law governing the fields created by currents is discussed in this section.

There are both direction and magnitude magnetic fields. The magnitude of the field can be determined by hall probes. There is a field around a long wire.

The rule is in line with the field mapped for the long straight wire.

The magnitude of the field is dependent on distance from the wire and not on position along the wire.

A magnetic field twice the strength of the Earth's would be created by finding the current in a long straight wire.

Due to the wire, the Earth's field is taken to be. Since all other quantities are known, the equation can be used to find it.

A large current produces a magnetic field that is close to a long straight wire. Since the Earth's field is specified to only two digits, the answer is stated to only two digits.

You might think that the magnetic field of a long straight wire is inconsequential. The total field of any shape current is the sum of the fields due to each segment. The field needs to be summed for an arbitrary shape current. The realization that electric and magnetic fields are different manifestations of the same thing led to the modern theory of relativity. The amount of space that can be devoted to it is beyond the scope of the text. For the interested student, and particularly for those who continue in physics, engineering, or similar fields, looking into these matters further will reveal descriptions of nature that are elegant as well as profound. We will keep the general features in mind, such as RHR-2 and the rules for magnetic field lines listed in Magnetic Fields and Magnetic Field Lines, while focusing on the fields created in certain important situations.

Sometimes we get the impression that Einstein invented something when we hear about him. Einstein's motivation was to solve difficulties in knowing how different observers see magnetic and electric fields.

The direction and magnitude of the magnetic field produced by a current-carrying loop are complexample RHR-2 can be used to give the direction of the field near the loop, but mapping with compasses and the rules about field lines given in Magnetic Fields and Magnetic Field Lines are needed.

Where is the loop located? The equation is very similar to one for a straight wire, but only valid at the center of the loop of wire. Field strength can be obtained at the center of a loop if the equations are similar. One way to get a larger field is to have loops. The larger the loop, the smaller the field at its center.

The field is similar to a bar.

The field inside a solenoid can be very strong because of its shape. The field is very cold.

The field is very cold.

The magnetic field inside of a current-carrying solenoid is very uniform. Only near the end does it begin to weaken and change direction.

The field strength is not only at the center, but also in the uniform region of the interior. Large uniform fields can be spread over a large volume with solenoids.

The field strength is found by using.

This is a large field strength that can be established over a large-diameter solenoid. The fields of this strength are not easy to achieve.

A large current through 1000 loops squeezing into a meter's length would produce significant heating. Superconducting wires can be used to achieve higher currents. There is an upper limit to the current since the state is disrupted by large magnetic fields.

There are many variations of the flat coil. The toroidal coil used to confine the particles in tokamaks is similar to a solenoid bent into a circle. The field inside a toroid is very strong. The charged particles travel in circles and collide with one another. The charged particles don't cross field lines. Magnetic field shapes can be produced with a range of coil shapes. Adding ferromagnetic materials can have a significant effect on the shape of the field.

The Earth's magnetic field is adversely affected by magnetic fields in ferromagnetic materials and they are used as shields for devices that are adversely affected.

You can learn how to make a bulb light using magnets.

Since ordinary currents produce magnetic fields and these fields exert significant forces on ordinary currents, you might expect that there are significant forces between wires. The force between wires is not used to define the ampere. This force has something to do with why large circuit breakers burn up when they attempt to interrupt large currents.

The force between two conductors separated by a distance can be found by applying what we have developed in preceding sections. Let's consider the field produced by wire 1 and the force it exerts on wire 2.

When the currents are in the same direction, the force between the parallel conductors is attractive. The force between the currents is repulsive.

The forces on the wires are equal in magnitude, and so we just write for the magnitude. The force per unit length is convenient since the wires are long.

The force per unit length between two parallel currents is 22.32. The force is attractive if the currents are both repulsive and in the same direction.

The pinch effect is caused by this force. Whether the currents are in wires or not, the force exists. An attraction that squeezes currents into a smaller tube is found in an electric arcs. The pinch effect can cause an arcs between plates of a switch trying to break a large current, burn holes, and even ignite the equipment.

There are jets of ionized material, such as solar flares, that are shaped by magnetic forces.

The definition of the ampere is based on the force between wires.

The force per meter is exactly what it is. The operational definition of the ampere is based on this.

One ampere of current through each of two parallel conductors of infinite length, separated by one meter in empty space free of other magnetic fields, causes a force on each conductor.

Infinite-length straight wires are impractical and so, in practice, a current balance is constructed with coils of wire separated by a few centimeters. Current is determined by force. The method for measuring the coulomb is provided by this. We measure the charge in a second. The method of measuring force between conductors is the most accurate for both the ampere and coulomb.

The charged particles in the magnetic fields can lead to curved paths. A charged particle moves in a circular path with a radius.

The relationship could be used to measure the mass of charged particles. A mass spectrometer is used to measure the mass. Magnetic fields are used for this purpose in most mass spectrometers. There are many possibilities since there are five variables. The radius of the path is proportional to the mass of the charged particle if,, and can be fixed. Let's look at a mass spectrometer that has a simple design. The process begins with a device called an ion source. The ion source gives the charge to the ion and then directs a beam of it into the next stage of the spectrometer. This region only allows particles with a certain value to get through.

The mass spectrometer uses a velocity selector to fix so that the path is proportional to mass.

There is an electric field and a magnetic field on opposite sides of the ion.

The charged particles move in circular arcs in the final region because there is only a uniform magnetic field. Since the paths are in multiples of electron charges, it is easy to discriminate between ion in different charge states.

Mass-to-charge ratios are used in chemistry and biology laboratories to identify chemical and biological substances. Mass spectrometers are used in medicine to measure the concentration of isotopes. Normally, large biological molecules are broken down into smaller fragments before analyzing. Mass spectrometers have been used to analyze large virus particles. Sometimes a gas chromatograph or high- performance liquid chromatograph can provide an initial separation of the large molecule, which is then input into the mass spectrometer.

Different versions of the electron gun are created by them. Magnetic fields are used to steer the electrons. Two pairs of coils are used to steer the electrons to their destinations.

The CRT is named because the rays of electrons originate at the cathode in the electron gun. Magnets are used to steer the beam. The beam is moved down. The beam would be steered by a pair of horizontal coils.

It does not use x-rays to produce two-dimensional and three-dimensional images of the body. The small magnetic fields of the nuclei are similar to those of electrons and the current loops discussed earlier in the chapter.

When placed in an external magnetic field, the nuclei experience a Torque that pushes them into one of two new energy states, depending on the orientation of their spin. Transitions from the lower to higher energy state can be achieved by flipping the orientation of the small magnets. The energy in the radio waves and the direction of the nuclear magnetic field are quantized. Depending on the type of nucleus, the chemical environment, and the external magnetic field strength, the specific frequencies of the radio waves that are absorbed and reemitted can be different.

This is a resonance phenomenon in which nuclei in a magnetic field act like resonators that absorb and reemit only certain frequencies. Nuclear magnetic resonance is a phenomenon.

For more than 50 years, NMR has been used as an analytical tool. The 1952 Nobel Prize in Physics went to F. Bloch and E. Purcell for their work on it.

There is an implication that nuclear radiation is involved. P. Lauterbur and P. Mansfield won the medicine prize in 2003 for their work on magnetic resonance applications.

The biggest part of the unit is a superconducting magnet that creates a magnetic field between 1 and 2 T in strength. Magnetic resonance images can give a lot of information about structures and functions. Normal and non-normal tissues respond differently to magnetic field changes. The protons that are hydrogen nuclei are imaged in most medical images. Their location and density give a variety of medically useful information, such as organ function, the condition of tissue (as in the brain), and the shape of structures. Magnetic resonancei can be used to follow the movement of certain ions across the membranes, yielding information on active transport and other phenomena. Information about tumors, strokes, shoulder injuries, and infections can be provided with excellent spatial resolution.

The density of a nuclear type is one of the requirements for an image. By changing the magnetic field slightly over the volume to be imaged, the resonance of the protons can be changed. If the nuclei are in a magnetic field with the correct strength, broadcast radio frequencies are swept over an appropriate range. The information gathered by the receiver is used to build a tissue map. The reception of radio waves gives position information. The cross sections through the body are only a few millimetres thick. The intensity of the radio waves is determined by the concentration of the nuclear type being flipped, as well as information on the chemical environment in that area of the body.

Enhancement of contrast in images is possible with various techniques. Different relaxation mechanisms of the nucleus are used in scans called T1, T2, or proton density scans. The time it takes for the protons to return to equilibrium is called relaxation. This time is determined by tissue type and status.

Magnetic resonance images are superior to x rays for certain types of tissue, but they do not completely replace x-ray images. The two diagnostic tools complement each other because x rays are less effective at detecting breaks in bone than magnetic resonance. Magnetic resonance images are more expensive than simple x-ray images and are used more often where there is not much information available from x rays. Claustrophobia can be caused by the fact that the patient is completely enclosed with detectors close to the body for 30 minutes or more. The obese patient can't be in the tunnel. The new open-MRI machines do not completely surround the patient.

Functional Magnetic Resonance Identification (fMRI) has allowed us to map the functioning of various regions in the brain responsible for thought and motor control. Blood flow in the brain is measured by this technique. The nerve cells use more oxygen when they are active. Blood hemoglobin has different magnetic properties when it is oxygenated than when it is deoxygenated. We can detect a blood oxygen- dependent signal with the use of magnetic resonance. fMRI is used in most of the brain scans.

Since their strengths are about to be less than the Earth's magnetic field, it's difficult to measure them. Both give information that is different from what is obtained by measuring the electric fields of these organs, but they are not important enough to make them common.

The sensors don't touch the body. It is more sensitive than echocardiography and can be used in fetal studies. The heart's electrical activity is too small to be recorded by surface electrodes as in the EKG. It has the potential to be used for an early diagnosis of Cardiac Ischemia or problems with the fetus.

Weak magnetic signals can be found in abnormal electrical discharges in the brain. It looks at brain activity, not just brain structure. It has been used to study Alzheimer's disease. The techniques of measuring very small magnetic fields have been improved in recent years. The SQUID is used for the quantum interference device.

Magnetic cures can be applied in a variety of ways to the body, from magnetic bracelets to magnetic mattresses. Unless the magnets get close to the patient's computer or magnetic storage disks, they are apparently harmless. Clinical studies have not verified the claims of a broad spectrum of benefits from cleansing the blood to giving the patient more energy, but there is an identifiable mechanism by which such benefits might occur.

You can see how things change inside and outside by adjusting the magnet's strength. The magnetic field can be measured using the field meter.

There are two types of magnetic poles.

The direction of the force on a moving charge is determined by the thumb of the right hand.

They have magnets that cross them.

It is not possible to separate the north and south Magnetic Field.

magnetism is created by electric current

ferromagnetic materials, such as iron, have strong magnetic effects and can supply centripetal force.

The atoms in ferromagnetic materials act like small magnets and are 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609- 888-609-

Permanent magnets are produced by the Hall Effect. The Hall effect is the creation of voltage, also known as the magnetized, or inducing to be magnetic.

Electric currents are used to make for a conductor of width through which charges move magnetic fields.

Magnetic field lines can be used to represent the magnetic force on conductors, where is the current, and the length of a straight 1. The field is parallel to the magnetic field line.

Field strength is determined by line density.

The force follows RHR-1. Field lines can't cross.

Field lines are repeated.

The magnetic field strength inside a solenoid is Ampere's Law where is the number of loops per unit length. A long straight wire is given by and direction to the field inside.

The magnetic force between two parallel currents is the shortest distance to the Parallel Conductors wire.

Do you think the magnetic field will fill the gap between the rapid decrease in strength and the distance from the plates associated with continental drift?

A charged particle might cross through a magnetic field line.

Magnetic field lines and electric field lines are similar. The field direction is at any point in space. List the ways in which they differ. Magnetic force on moving charges is parallel to magnetic field lines.

Discuss how the Hall effect can be used to get information on free charge density.

There are high-velocity charged particles that can damage biological 22.7 Magnetic Force on a Current- cells and are a component of radiation exposure in a Carrying Conductor variety of locations.

The direction of the force on the wire can be verified if a Cosmic Ray proton approaches the Earth.

The charges carry the current across the fluid.

The direction of the Torque on the loop is the same as repelling poles and attracting poles.

During maintenance, a high-precision TV monitor is placed on its side. The image on the monitor is blurry.

The electric field lines can be protected.

Magnetic fields associated with brain activity are measured.

Two long wires run parallel to each other. Discuss the same effect on wires without touching. Does one use a net pacemaker?

Justify your responses by using the right hand side.

To justify your answers, draw sketches.

The Earth's magnetic field interacts with this fluid to create a potential difference between the two river banks.

Explain the differences between the fields and the entities responsible for them.

There are two loops of wire carrying currents.

What is the direction of the charge going down.

There are answers.

A mass spectrometer is being used to separate oxygen-16 from oxygen-18 from the Earth's magnetic field at an altitude. What is the sample of ice?

What is the difference between the two ships?

Antimatter is being separated.

The antiprotons have the same field. There is a negative charge between their protons.

The Hall Effect magnetic field makes it move in a circular pattern.

An electron moves with a speed of flows as a result of the Hall voltage.

The Hall voltage must be measured and the strength electric field applied.

A 0.20-T field is placed in the direction of the magnetic field that produces a 2.00-T field.

A wire carrying a 30.0-A current passes between the poles of a strong magnet and experiences a 2.16-N force on the 4.00 cm of wire in the field.

A protons spin on its axis and has a magnetic field.

The net force on the loop should not be affected by the maximum Torque found.

When viewed from the east, a current of 100 A circulates clockwise. The Earth's field is due north, parallel to the ground.

A loop of wire carrying a current. What is the magnitude and direction of the magnetic field?

The force between the two wires of a jumper is 0.225 N/m.

Find the current through a loop that is needed to create a parallel wire.

The directions of the fields are in the center of the loop.

To see why iron is used to increase the magnetic field created by a coil, calculate the current needed to create a 1.20-T field at its center with no iron present.

30.0 A passes through a circular loop that is 10 cm in diameter.

A long straight wire carries the current.

The current loop in the loop creates by calculating the field at the center of a circular loop 20.0 cm in diameter carrying 5.00 A affects the system being measured.

The loop carries a current.

You should include a free-body diagram in your analysis.

Find the magnitude and direction of the magnetic field at the point equidistant from the wires.

Find the magnitude and direction of the magnetic field at the point equidistant from the wires.

Integrated Concepts has a power line.

The 1.20-T field of a cyclotron has a 25.0-MeV protons moving in a straight line.

A 0.500-T magnetic field is placed across the supply water pipe to a home in order to build a non mechanical water meter.

The maximum Torque on a 50-turn, 1.50 cm baseball, pitched at 40.0 m/s horizontally and carrying in a and parallel to the Earth's horizontal 0.500-T field was calculated.

Both are close to the ground. Field strength is determined by the percent change in force per degree.

Integrated Concepts has a magnetic field. The lower that these results are independent of the velocity and wire carries 100 A and the wire 7.50 cm above it is the energy of the 10-gauge copper wire.

Unreasonable results include finding the charge on a baseball thrown at 35.0 m/s that experiences a 1.00-N magnetic force.

A charged particle with mass moving at metal Dees, between which the particles move, so that it travels in a circular path of a 1.50-T magnetic field.

An inventor wants to generate power by moving.

Consider a mass separator that applies a magnetic field flow measurement, a medical physicist decides to apply the magnetic field strength to the path of the ion in order to get the ion based on the radius of the path in 0.500-V output for blood moving at 30.0 cm/ The 1.50- cm-diameter vessel is a problem you can solve.

The velocities they can be given before entering the A 100 m from a long straight 200-kV DC power magnetic field and a reasonable value for the radius of line suspects that its magnetic field may equal that of the paths they follow. The Earth and compass readings are affected by this.

The maximum Torque on a current-carrying loop in a magnetic field can be calculated. The size of the coil, the number of loops it has, the current you pass through it, and the size of the field you want to detect are some of the things to consider. Discuss if the Torque produced is large enough to be measured. Your instructor may want you to consider the effects of the field produced by the coil on the surroundings that could affect detection of the small field.