Electricity in Physics - Physics | General Awareness & Knowledge - Bank Exams PDF Download

Electric current

• An electric current is a flow of electric charge through an electrical conductor.
• In electric circuits this charge is often carried by moving electrons in a wire.
• It can also be carried by ions in an electrolyte, or by both ions and electrons such as in a plasma.
• The SI unit for measuring an electric current is the ampere, which is the flow of electric charges through a surface at the rate of one coulomb per second.
• Electric current can be measured using an ammeter.

Direct & Alternating current

• Direct current (DC) is the unidirectional flow of electric charge.
• Direct current is produced by sources such as batteries, thermocouples, solar cells, and dynamo .
• In alternating current (AC), the movement of electric charge periodically reverses direction.

Electromagnetism

• Electric current produces a magnetic field. The magnetic field can be visualized as a pattern of circular field lines surrounding the wire that persists as long as the current flows.
• Magnetism can also produce electric currents.
• When a changing magnetic field is applied to a conductor, an EMF is produced, and when there is a suitable path, this causes current to flow.
• Electric current can be directly measured with a galvanometer

Electromagnetism 

 Generating Electrical Current

• Electrical current can be generated by moving a metal wire through a magnetic field.
• This applies both to alternating current (AC) and direct current (DC) electricity.
• This is a different method than where DC is created by a battery, which uses chemical reactions.

Generation of electric current

• Electrical generators rotate a coil of wires through a magnetic field.
• An electric motor is very similar to a generator, except that power is provided to turn the rotors.

Electrical Generators 

 Hydel-Power station

Hydel Power Station

Fuse Wire

• Fuse Wire is used in a circuit to control the maximum current flowing in a circuit. It is a thin wire having high resistance and is made up of a material with low melting point.