1. The area around a magnet which exerts a magnetic force, is called a magnetic field. It is produced by moving electric charges.

Electric fields are generated around particles that bear electric charge. Positive charges are drawn towards it, while negative charges are repelled. The moving electric charge causes an increase in the electric field in front of it and a decrease in the electric field in back of it, and these changes create a magnetic field.

A moving charge always has both a magnetic and an electric field, and that's the reason why they are associated with each other. They are two different fields with nearly the same characteristics. Therefore, they are inter-related in a field called the electromagnetic field. In this field, the electric field and the magnetic field move at right angles to each other. However, they can exist independently, and not dependent on each other. Without the electric field, the magnetic field exists in permanent magnets and without the magnetic field, electric fields exist in the form of static electricity.

Electricity and magnetism are two related phenomenaproduced by the electromagnetic force. Together, they form electromagnetism.

• A moving electric charge generates a magnetic field.
• A magnetic field induces electric charge movement, producing an electric current.
• In an electromagnetic wave, the electric field and magnetic field are perpendicularto one another.

2. Flowing electrons produce a magnetic field, and spinning magnets cause an electric current to flow. Electromagnetism is the interaction of these two important forces. Electricity and magnetism are integral to the workings of nearly every gadget, appliance, vehicle, and machine we use.

Humans use our knowledge of this electromagnetic radiation. We build telescopes for viewing the heavens, radios to communicate, and X-ray machines for check for broken bones. Our society uses electricity in many ways. Generators in power plants change heat from steam into electricity. That electricity flows along wires to our houses and schools. We flip a switch to turn on a light, a fan, or a dishwasher. Chips in computers use electricity to "think" and calculate. Small electrical currents carry information, like this Web page, over the Internet to your computer's screen.

Electromagnetics EM is the study of the underlying laws that govern the manipulation of electricity and magnetism, and how we use these laws to our advantage. Hence, electromagnetics is the source of fundamental principles behind many branches of electrical engineering, and indirectly impacts many other branches. For example, many laws in circuit theory can be derived from laws of EM. The increased clock rates of computers make the electrical signals in computer circuits and chips more electromagnetic in nature, meaning that mastering their manipulation requires a fundamental understanding of EM. EM includes the study of antennas, wireless communication systems, and radar technologies. In turn, these technologies are supported by microwave engineering, which is an important branch of EM. Traditionally, the understanding of EM phenomena has been aided by mathematical modeling, where solutions to simplified models are sought for the understanding of complex phenomena. That's why study/ Research of electromagnetism is very important.

3. Common ailments for which magnetic healing is thought to provide some relief include arthritis, back pain, carpal tunnel syndrome, sinus and stress headaches, asthma, muscle spasms, toothaches, strains, joint pain, fractures, and swelling.

• Magnets have two different poles a positive pole and a negative pole. For reasons most researchers cannot explain, applying the negative side of a magnet is effective, but applying the positive side of a magnet is not.
• The force (magnetic field of energy) from a magnet is measured in gauss strength. Magnets used for pain relief and healing typically measure between 300-1000 gauss. (By the way, don't expect any relief from your common refrigerator magnets, which aren't strong enough: They're usually only around fifty gauss.)
• There are two kinds of magnets: permanent and pulsating. Permanent magnets provide a consistent and steady magnetic field, and are the type used to combat pain. Pulsating magnets don't provide a steady magnetic field, but have been used to stimulate growth in broken bones.
• Magnetic healing products come in a variety of shapes and sizes, from wrist and ankle jewelry to Velcro wraps to magnet-filled pads to fit on your bed.
• Wraps and jewelry can be placed in several spots on your body, including feet, ankles, knees, hips, back, hands, wrists, shoulders, neck, and forehead.

4. A magnetic field is not just an electric field with relativity applied, i.e. an electric field viewed from the wrong reference frame. In reality, a magnetic field is a fundamental field which can exist in a certain reference frame without needing any help from an electric field. More generally, both electric fields and magnetic fields are part of one fundamental, unified entity: the electromagnetic field.

Electric and magnetic fields obey a set of physical laws called Maxwell's equations. Einstein's theory of Special Relativity describes how space and time change depending on the choice of inertial reference frame. It turns out that Special Relativity is automatically contained in Maxwell's equations. In fact, Einstein discovered Special Relativity by closely scrutinizing and understanding Maxwell's equations. Therefore, using Maxwell's equations in relativistic form, we can figure out how to mathematically transform electric and magnetic fields from one reference frame to another. In other words, if I measure and map out the electric and magnetic fields in a room while I am standing motionless on the ground, then by applying the relativistic frame transformations to these field expressions I know what the fields will look like to an observer that is coasting through the room on roller skates. These electromagnetic relativistic frame transformation equations have been experimentally found to be correct.

5. When a magnetic field gets stronger than about 500,000 Gauss, objects get ripped to pieces by the intense forces. For this reason, scientists cannot build a machine that creates a magnetic field stronger than 500,000 Gauss and survives longer than a fraction of a second.

While the destructive nature of strong magnetic fields places a practical limit on how strong of a field earthlings can create, it does not place a fundamental limit. Magnetic fields that surpass about a billion Gauss are so strong that they compress atoms to tiny needles, destroying the ordinary chemical bonds that bind atoms into molecules, and making chemistry as we know it impossible. Each atom is compressed into a needle shape because the electrons that fill most of the atom are forced by the magnetic field to spin in tiny circles. While such extremely strong magnetic fields are not possible on earth, they do exist in highly-magnetized stars called magnetars.

6. Magnetism in metals is created by the uneven distribution of electrons in atoms of certain metal elements. The irregular rotation and movement caused by this uneven distribution of electrons shift the charge inside the atom back and forth, creating magnetic dipoles.

When magnetic dipoles align they create a magnetic domain, a localized magnetic area that has a north and a south pole.

In unmagnetized materials, magnetic domains face in different directions, canceling each other out. Whereas in magnetized materials, most of these domains are aligned, pointing in the same direction, which creates a magnetic field. The more domains that align together the stronger the magnetic force.

7. The north pole of a compass magnet points toward the north. Earth's south magnetic pole is near Earth's geographic north. Earth's magnetic north pole is near Earth's geographic south. That's why the north pole of a compass points toward north because that's where Earth's south magnetic pole is located and they attract.

A magnetic compass needle pointing North and South shows deflection when a bar magnet or a current carrying loop is brought near it. This happens because the magnetic fields of the compass needle and the bar magnet (or current carrying loop) interact with each other.

Salient features of magnetic field lines:-

1. Magnetic field lines follow the direction from the north pole to the south pole.
2. Magnetic field lines always show concentric pattern.
3. Magnetic field lines do not cross one another.
4. Closer the field lines; stronger is the magnetic field and vice-versa is also true.
5. Magnetic field lines are closer near the poles; which shows greater strength of magnetic field near the poles.

8. Three Topic in Magnetism that I find most interesting are:

1. Eddy Currents:

These are electrical currents that are induced when a magnetic field moves in relation to an electrical conductor that has been placed within reach of the magnetic field. In turn, these eddy currents create a magnetic field that acts to stop the relative motion of the original magnetic field and electrical conductor.

2. Magnetic Strength:

The most powerful magnets available today are the rare- earth types. Of the rare-earths, neodymium magnets are the strongest. However, at elevated temperatures (of approximately 150C and above), samarium cobalt magnets can be stronger than neo magnets, depending on the magnetic circuit.

Most commonly, Gaussmeters, magnetometers, or pull-testers are used to measure the strength of a magnet. Gaussmeters measure the strength in Gauss; Magnetometers measure in Gauss or arbitrary units (making it easy to compare one magnet to another); pull-testers measure pull in pounds, kilograms, or other force units. Helmholtz Coils, search coils and permeameters are also used to make sophisticated measurements of magnets.

Special Gaussmeters can cost up to several thousands of dollars. Integrated Magnetics stocks several types of Gaussmeters that range between $400 and $1,500 each. contact us if you are interested in more information regarding these or to place an order.

3. Force on current in Magnetic Field:

The motion of electrically charged particles gives rise to magnetism. The force acting on an electrically charged particle in a magnetic field depends on the magnitude of the charge, the velocity of the particle, and the strength of the magnetic field. All materials experience magnetism, some more strongly than others.

9. The four main factors that affect the strength of an electromagnet are the loop count, the current, the wire size, and the presence of an iron core.

1. The strength of the magnetic field of an electromagnet increases when: (a) The current is increased (b) The number of turns is increased (c) The turns of wire are pushed closer together so that the length of the solenoid becomes shorter (d) A soft iron core is placed into the solenoid
2. The use of alloys such as aluminum-nickel- cobalt (alnico) can produce stronger magnetic fields.
3. The polarity at the ends of the solenoid is changed by changing the direction of the current.

10.

Magnets are used to make a tight seal on the doors to refrigerators and freezers. They power speakers in stereos, earphones, and televisions. Magnets are used to store data in computers, and are important in scanning machines called MRIs (magnetic resonance imagers), which doctors use to look inside people's bodies.

• A magnet is used in a compass to show the direction.
• Powerful magnets are used to lift objects.
• Magnets are used in generators and motors.
• Prevents corrosion in a water heater.
• Magnets are used in medical equipment.

11. In accordance with the Standard Model of particle physics, protons and neutrons make up the nucleus of the atom, while electrons orbit it in a "cloud". The electrons in an atom are attracted to the protons in the nucleus by the electromagnetic force.

Each atom has electrons, particles that carry electric charges. Spinning like tops, the electrons circle the nucleus, or core, of an atom. Their movement generates an electric current and causes each electron to act like a microscopic magnet. The electron configuration of the atoms found within a substance will affect its magnetic properties. Many pure substances, besides iron metal, are attracted to a strong magnetic field.

12. Magnets lose their property when heated, hammered or dropped from a height.

If a magnet is exposed to high temperatures, the delicate balance between temperature and magnetic domains is destabilized. At around 80 C, a magnet will lose its magnetism and it will become demagnetized permanently if exposed to this temperature for a period, or if heated above their Curie temperature.

13. The Faraday paradox or Faraday's paradox is any experiment in which Michael Faraday's law of electromagnetic induction appears to predict an incorrect result. The paradoxes fall into two classes: Faraday's law appears to predict that there will be zero electromotive force (EMF) but there is a non-zero EMF.

14. The larger diameter core required slightly less current than the smaller diameter, and the U-bracket that didn#t extend all the way to the top of the solenoid decreased the required current significantly. The bias magnets dramatically reduced the required current.

I increased the efficiency (power usage in watts) of my solenoid by 92% from last year#s solenoid with the tube core. A U-bracket that extends the core around the solenoid, but not too far, increases efficiency. Bias magnets can effectively compensate for both the weight of the target arm and the sticking force of the target arm magnet to the core.

15. Tunnel magnetoresistance (TMR) is a magnetoresistive effect that occurs in a magnetic tunnel junction (MTJ), which is a component consisting of two ferromagnets separated by a thin insulator. If the insulating layer is thin enough (typically a few nanometers), electrons can tunnel from one ferromagnet into the other.

Magnetic tunnel junctions (MTJ) are promising candidates for the spintronic devices. They are not only important for the futuristic memory devices but also interesting for their fundamental effects such as tunneling, magnetoresistance, and spin-transfer torque. Thus attempts are made to develop good quality junctions.