Similar to electric charges, how the poles exert a repulsive force on each other, while the opposite poles exert a force of attraction on each other. Materials can be classified as magnets, magnetic attractable (materials that are not magnets themselves but can be attracted to magnets) and non-attractable. Question: The following diagram shows the magnetic lines of force between two magnetic north poles. When is the magnetic field strength greatest? Magnets are very useful tools that we use every day without realizing it. Did you know that magnets are present in the computers we use or the televisions we watch? Yes, that`s right! Many of the devices we use contain magnets of different sizes, from barely visible dots to gigantic places. Permanent magnets do not lose their magnetism so easily. It is a piece of material that retains its magnetism even when not exposed to external magnetic fields. Some examples are alnicos and ferrites. Answer: At least one of the pieces of iron is a magnet, but we cannot say with certainty that both are magnets. As you already know, magnets are objects that can attract or repel other magnetic materials or metals such as iron and steel. But why is this happening? Question: Draw at least four field lines to show the size and direction of the magnetic field in the region around a magnetic bar. Electromagnets are created by placing a metal core in a coil of wire that transmits electric current. The energized core forms a magnetic field.

When the power is cut off, the magnetic field disappears. Devices such as televisions and computers use electromagnets. Answer: (B) has the highest magnetic field strength because it is at the highest density of magnetic field lines. There are 3 different types of magnets: temporary, permanent and electromagnetic. They are classified according to their magnetism. Answer: (1) Gravity can only attract, and because magnet A hovers above magnet B, the magnetic force must be repulsive. The most fundamental law of magnetism is that, unlike the poles, the poles attract each other and, unlike the poles, repel each other. The strongest gravitational pullations in a magnetic object are located at both ends, the North Pole and the South Pole. Magnetism is closely related to electricity. Essentially, magnetism is a force caused by moving charges.

In the case of permanent magnets, the moving charges are the orbits of electrons rotating around nuclei. Basically, powerful permanent magnets have many atoms with electrons rotating in the same direction. Non-magnets have more random arrangements of electrons revolving around the nucleus. In the case of electromagnets, the current itself provides the moving charges. In any case, magnetic fields can be used to describe the forces caused by magnets. Answer: (3) An electric field is present because of the electric charge, and a magnetic field is present because the charge is moving. Here you can learn about the fundamental laws of magnetism and the magnetic properties of matter. Question: A student is given two pieces of iron to determine if one or both parts are magnets.

First, the student touches one end of a room with one end of the other. The two pieces of iron attract. Then the student reverses one of the parts and touches the ends together again. The two pieces attract each other again. What certainly does the student know about the initial magnetic properties of the two pieces of iron? Question: If two ring magnets are placed on a pencil, magnet A gets stuck on magnet B, as shown on the right. What statement describes the gravitational force and the magnetic force acting on magnet A due to magnet B? All objects have many tiny particles called atoms. Each atom has electrons that carry electric charges. The movement of electrons creates an electric current that creates a magnetic field. They used electric field lines to visualize what would happen to a positive charge in an electric field. To visualize a magnetic field, you can draw magnetic field lines (also called magnetic flux lines) that show the direction in which the north pole of a magnet would point if placed in the field. Magnetic field lines are traced as closed loops that emanate from the north pole of a magnet and continue to the south pole of a magnet.

Inside the magnet itself, the field lines run from the South Pole to the North Pole. The magnetic field is strongest in areas with the highest density of magnetic field lines or areas with the highest magnetic flux density. The strength of the magnetic field (B) is measured in units called Tesla (T). If your child needs O level physics classes, you should sign up with us! Our experienced tutor can help your child learn more about the different concepts and laws of physics and push them to do more in school! Start teaching physics today! To induce magnetism on an object, a highly magnetic material such as iron or steel must enter the magnetic field of an existing magnet. For example, if you stroke a piece of iron along a magnet, the poles of the atom looking for north will organize in the same direction. A magnetic field is generated by the force generated by aligned atoms. Therefore, this piece of iron becomes a magnet. Which statement best describes the forces between magnetic bars? The laws of magnetism profoundly influence our daily lives. Many of the devices we use or activities we do are made of magnets. Learning the basic laws of magnetism can help you see the world in a different light.

Temporary magnets are magnetized in the presence of a magnetic field. Other materials that can act as a temporary magnet are paper clips and nails. Magnets are polarized, which means that each magnet has two opposite ends.