Deep inside the Earth, the movement of liquid iron in the core creates electric currents, which in turn generate a magnetic field.

The heat generated depends on the magnitude of the electric current (which increases when using more cells/batteries).

The Voltaic or Galvanic cells get their names from two Italian scientists, Alessandro Volta and Luigi Galvani.

The strength of an electromagnet can be changed by changing the amount of electric current flowing through the coil or the number of turns of the coil, or both.

When electric current flows through a conductor (like a wire), it produces a magnetic field around it. This is known as the magnetic effect of electric current.

Dry cells are called ‘dry’ because the electrolyte is not a liquid but a thick moist paste.

Safety devices are placed in household circuits to minimize incidents caused by overheating in appliances, which can lead to damage to plugs/sockets or even fires.

The magnetic effect of electric current has many practical applications, such as in devices like electromagnets, electric bells, motors, fans, loudspeakers, and more.

The poles of an electromagnet can be reversed by changing the direction of the current flowing through the coil.

A current carrying coil that behaves as a magnet is called an electromagnet.

Hans Christian Oersted (1777–1851), a professor in Denmark, observed and published his findings that an electric current indeed produced a magnetic field.

A nichrome wire, for example, offers higher resistance compared to a copper wire of the same size and length, leading to significant heat generation.

The deflection indicates that the current-carrying wire has a magnetic effect on the compass needle, meaning a magnetic field is present around the wire.

Generation of heat in conductors due to flow of electric current is known as the heating effect of electric current.

For practical applications, most electromagnets have an iron core to make them stronger.

The dry cell consists of a zinc container which acts as a negative terminal.

Lifting electromagnets are used in factories and scrap yards to move, lift, and sort heavy iron/steel objects. The magnet is controlled by switching the current ON and OFF.

Household appliances like electric room heaters, stoves, irons, immersion rods, water heaters, kettles, and hair dryers work on the principle of the heating effect of electric current.

A Voltaic cell is a device that generates electric current due to chemical reactions taking place inside it, consisting of two metal plates (electrodes) and an electrolyte.

Many household appliances contain a rod or a coil of wire, called a heating element.

When making a lemon cell using copper wires/strips and iron nails, the lemon juice acts as the electrolyte, helping to conduct electricity.

When electric current flows through a conductor, it faces some opposition or resistance to its flow, causing some of the electrical energy to be converted into heat energy.

When the current stops flowing, the magnetic effect disappears, and the compass needle returns to its original direction.

The plates, called electrodes, are partly dipped in the liquid called an electrolyte, which is usually a weak acid or salt solution.

The dry cell is a single use cell, meaning once it is used up, it has to be disposed of, unlike rechargeable batteries.