Electromagnetism

When a bar magnet is inserted into a solenoid, the solenoid will cut the magnetic flux of the bar magnet. This will induce a current and emf in the solenoid. The induced current will produce another magnetic field around it. The pole of the magnetic field and direction of the induced current can be determined … Read more

When a straight conductor (or wire) moves and cut a magnetic field, emf will be induced across the conductor. If the conductor is in a complete circuit, the current will flow in the conductor. The direction of the current induced can be determined by using Fleming’s Right Hand Rule, as explained in the video below. … Read more

There are 2 principal laws of electromagnetic induction: Faraday’s law Lenz’s law Faraday’s Law The magnitude of the induced e.m.f is determined by Faraday’s Law. Faraday’s Law states that the magnitude of the induced e.m.f is directly proportional to the rate of change of magnetic flux through a coil or alternatively the rate of the … Read more

When a magnet is moved into and out of the solenoid, magnetic flux is being cut by the coil.  The cutting of magnetic flux by the wire coil induces an e.m.f in the wire.  When the solenoid is connected to a closed circuit, the induced current will flow through the circuit. The production of electric … Read more

When 2 current-carrying conductors are placed close to each other, a force will be generated between them. If the current in both conductors flows in the same direction, they will attract each other, whereas if the current is in opposite direction, they will repel each other. This force is due to the interaction between the … Read more

Loud Speaker The loudspeaker contains a cylindrical coil which is free to move in a radial magnetic field set up by a strong cylindrical permanent magnet. The magnet has the central South Pole and the surrounding North Pole. The field lines are therefore radial and at right angles to the turns of the coil. When … Read more

An electric motor converts electrical energy to kinetic energy. The diagram above shows the structure of a simple direct current motor (DC motor). It consists of a rectangular coil of wire placed between 2 permanent magnets. The coil is soldered to a copper split ring known as a commutator. 2 carbon brushes are held against … Read more

Light Indicator A light indicator which has lower inertia is used to increase the sensitivity of the meter. Linear Scale Due to the radial magnetic field and the cylindrical soft-iron core, a linear scale is produced. A linear scale is more accurate and easier to be read. Mirror A mirror is used to prevent parallax … Read more

If a current-carrying coil is placed in a magnetic field (As shown in the diagram above), a pair of forces will be produced on the coil. This is due to the interaction of the magnetic field of the permanent magnet and the magnetic field of the current-carrying coil. The diagram below shows the catapult field … Read more

We have learned that when current flows in a conductor, a magnetic field will be generated. When the current-carrying conductor is placed in a magnetic field, the interaction between the two magnetic fields will produce a resultant field known as the catapult field as shown in the figure below. The catapult field is a non-uniform … Read more