DOMESTIC
ELECTRIC CIRCUITS
In homes, electric power is supplied through a main supply (mains), supported through overhead electric poles or by underground cables. In this, one wire is with red insulation cover (live wire or positive) and other wire is with black insulation (neutral wire or negative). In our country, the potential difference between the two is 220 V.
ELECTRIC
GENERATOR
The principle of electromagnetic induction can be applied to produce large currents for use in homes and industry.
ELECTROMAGNETIC
INDUCTION
Consider a conductor is moving inside a magnetic field or a magnetic field is changing around a fixed conductor. This was first studied by English experimental physicist Michael Faraday (1831). He discovered how a moving magnet can be used to generate electric currents. This effect can be observed by the following activity.
ELECTRIC MOTOR
It is a rotating device that converts electrical energy to mechanical energy.
An electric current through a conductor produces a magnetic field. This field exerts a force on a magnet placed near the conductor.
MAGNETIC
FIELD DUE TO A CURRENT-CARRYING CONDUCTOR
Electricity and Magnetism are linked to each other. It can be shown by the following experiment.
HEATING
EFFECT OF ELECTRIC CURRENT
A battery or a cell is a source of electrical energy. It generates potential difference that sets the electrons in motion to flow the current through a resistor or a system of resistors.
RESISTANCE
OF A SYSTEM OF RESISTORS
In electrical gadgets, resistors are used in various combinations based on Ohm’s law.
FACTORS ON
WHICH THE RESISTANCE OF A CONDUCTOR DEPENDS
Note the ammeter reading in an electric circuit with
OHM’S LAW
Set up a circuit consisting of a nichrome wire XY (0.5 m length), an ammeter, a voltmeter and four cells of 1.5 V each. (Nichrome = an alloy of Ni, Cr, Mn & Fe.)
ELECTRIC
POTENTIAL AND POTENTIAL DIFFERENCE
Electric charges do not flow in a metallic conductor (e.g. copper wire) by themselves. Here, gravity has no role.
ELECTRIC
CURRENT AND CIRCUIT
Flow of electric charges through a conductor (e.g., metallic wire) is called an electric current.
