Syedies

Back emf effect Motor The emf induced which opposes the emf running the motor is called the back emf of the motor. Explanation When the coil of the motor rotates across the magnetic field by the applied potential difference V, an emf is induced in it. The induced emf is in such a direction to … Read More “Back emf effect in motor” »

D.C. Motor It is a device that converts electrical energy into mechanical energy. Principle When the current-carrying coil is placed in a magnetic field. It experiences a force and rotates. Construction Its construction is similar to that of d.c. the generator works in the backward direction. The coil wound on a soft iron cylinder(core). The … Read More “DC Motor: Its principle, construction and working” »

The torque produced in the coil due to the current in the coil which opposes the rotational motion of the coil is called the back motor effect. Explanation A large turbine is turned by high pressure stream or waterfall. The shape of the turbine is attached to the coil which rotates in the magnetic field. … Read More “Back Motor Effect in Generators” »

DC Generator It is a device that converts mechanical energy into electrical energy and produces direct current and direct emf. Principle Its principle is based on Faraday’s law. When the coil rotates by any means in the magnetic field, the flux changes and produces directly induced emf. Construction Its Construction is the same as that … Read More “DC Generator its principle, construction and working” »

Alternating Current Generator It is a device that converts mechanical energy into electrical energy and generates alternating current is called an alternating current generator. Principle It principle is based on Faraday’s law, when a coil rotates by any means in the magnetic field, the magnetic flux through the coil changes and induced emf in coil. … Read More “Alternating Current Generator: its principle, construction, and working also derived expression for induced emf” »

Energy Stored in an Inductor Consider a coil connected to a battery through switch S. When the switch is turned on vol voltage Vis applied across the and of the coil current through rises from zero to its maximum value I. Due to the change of current, an emf is induced which is opposite to … Read More “Expression for Energy Stored in an Inductor and Energy density” »

Self Induction The phenomenon in which a changing current in a coil produces an induced emf in the same coil is called self-induction. Construction A coil, battery, and rheostat are connected in series through a switch S to form a circuit of self-induction. Working: When the current in the coil is changed by varying the … Read More “Self Induction, Circuit Construction, Working, Expression and unit” »

Mutual induction The phenomenon in which a changing current in one coil produces an induced emf in another coil is called mutual induction. Construction Primary coil The coil is connected to a battery through a switch and a rheostat is called the primary coil. Secondary Coil When the primary and the secondary coil are placed … Read More “Mutual Induction, its construction, Its working, drive its expression and unit” »

Lenz’s law and direction of induced EMF The direction of the induced current is always such to oppose the change which causes the current. Explanation Consider a coil in which current is induced by the movement of a bar magnet towards in coil. The magnetic field produces in the coil. one face of the coil … Read More “Define and explain Lenz’s Law” »

Faraday’s Law The average induced emf in conducting coil of the N loop is equal to the negative of N time the rate of change of magnetic flux through the coil. ε = -N (∆∅)/∆t Explanation The motional induced emf in a rod moving perpendicular to the magnetic field is given by ε = -VBL … Read More “Define and Explain Faraday’s Law” »