# MAGNETIC EFFECTS OF ELECTRIC CURRENT

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.

# MAGNETIC EFFECTS OF ELECTRIC CURRENT

ELECTRIC GENERATOR

The principle of electromagnetic induction can be applied to produce large currents for use in homes and industry.

# MAGNETIC EFFECTS OF ELECTRIC CURRENT

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.

# MAGNETIC EFFECTS OF ELECTRIC CURRENT

ELECTRIC MOTOR

It is a rotating device that converts electrical energy to mechanical energy.

# MAGNETIC EFFECTS OF ELECTRIC CURRENT

FORCE ON A CURRENT-CARRYING CONDUCTOR IN A MAGNETIC FIELD

An electric current through a conductor produces a magnetic field. This field exerts a force on a magnet placed near the conductor.

# MAGNETIC EFFECTS OF ELECTRIC CURRENT

MAGNETIC FIELD DUE TO A CURRENT-CARRYING CONDUCTOR

# MAGNETIC EFFECTS OF ELECTRIC CURRENT

Electricity and Magnetism are linked to each other. It can be shown by the following experiment.

# ELECTRICITY

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.

# ELECTRICITY

RESISTANCE OF A SYSTEM OF RESISTORS

In electrical gadgets, resistors are used in various combinations based on Ohm’s law.

# ELECTRICITY

FACTORS ON WHICH THE RESISTANCE OF A CONDUCTOR DEPENDS

Note the ammeter reading in an electric circuit with

# ELECTRICITY

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.)

# ELECTRICITY

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.

# ELECTRICITY

ELECTRIC CURRENT AND CIRCUIT

Flow of electric charges through a conductor (e.g., metallic wire) is called an electric current.