What is emf source? A source of electromotive force is a device in which non electrical energy is changed into electrical energy.Examples of e.m.f sources are electrical cells,thermocouples and generators. The e.m.f of the source is able to maintain its upper terminal positive and its lower terminal negative charge. When the switch is closed,the cell drives a clock wise current ...

What is Mutual induction? “The process of inducing e.m.f in the secondary coil by changing the magnetic flux of the primary coil with the help of varying current through it is called mutual induction.” If two coils placed together ,then by changing current in one coil sets up a changing magnetic field in the other coil,so induced an e.m.f in ...

What is the definition of biot savart law? “The magnetic induction at any point produced by current element is directly proportional to the product of the current and the differential element and inversely proportional to the square of distance of the point from the differential element.” Formula of Biot Savart law: Derivation of Biot Savart law: To explain the Biot ...

Analogies between Gauss’s law and Ampere’s law: Gauss’s law says the electric flux through a closed surface is proportional to the charge within the surface.Ampere’s law says the line integral of B.ds around a close path is proportional to the current that passes through that path. In Gauss’s law,the imaginary and arbitrary closed surface is taken enclosing a charge.In ampere’s ...

Similarities: Both the electric and magnetic field depends inversely on square of distance between the source and field point. Both electric field and magnetic field are proportional to the source strength namely charge and current element respectively. Both obey superposition principle. Differences: According to Coulomb’s law,the electrostatic force between two point charges is directly proportional to the product of their ...

A transformer cannot operate on a steady or unchanging dc voltage such as that of a battery.It requires a voltage which rises and falls.Since an ac voltage not only changes its magnitude but its direction as well,it is used to operate the transformers. However,a transformer will operate from dc voltage if this voltage also undergoes changes.Transformers used for audio amplifiers ...

What is eddy current? A current induced in a conductor when subject to a varying magnetic field.Such currents are a source of energy dissipation (eddy current loss) in alternating current machinery.The reaction between the eddy currents in a moving conductor and the magnetic in which it is moving is such as to retard the motion.This property of eddy currents is ...

Thermal effects: Joule’s law of heating: “The heat produced in a conductor is: (1) Directly proportion the square of current passing through the conductor,(H ∝ I²) keeping R and t constant; (2) Directly proportion to the resistance of the conductor (H ∝ R) keeping I and t constant;and (3)Directly proportional to the time of flow of current (H ∝ t) keeping I and ...

Applications of a step up transformer: For Transmission of electric power from power station to consumer,voltage is step up by using step up transformer.It minimizes the power loss in transmission line. Applications of a step down transformer: Step down transformer decrease the voltage to a safe value at the end of the transmission line where the consumer of electric power ...

Most larger power distribution systems are AC.The power is transmitted from power stations at much higher voltage to minimize the power loss.At the end of the line where the consumer is located,the voltage level is reduced to a safe value for domestic use.The crucial factor is that it is much easier to increase and decrease AC voltage than DC,so AC ...