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Class 10, Science, Chapter-11, Lecture-1, Electric Current (Notes)

ELECTRIC CURRENT:

The quantity of charge flowing through a cross section of a wire per unit time is termed as the electric current.

Mathematically   $$I\,\,\, = \,\,\,{Q \over t}$$     where I = magnitude of electric current
                 Q = quantity of charge flowing at a given point
                  t = time

S.I. Unit – ampere ( A )

Electric current is a scalar quantity

ONE AMPERE:

The flow of 1 coulomb of charge through a cross section of a wire in 1 second is 1 ampere of electric current.
    1 A = 1 C s–1

POTENTIAL DIFFERENCE:

The amount of work done in moving a unit positive charge from one point to another in an electric field is termed as the potential difference between two points.

Mathematically  $$V\,\,\, = \,\,\,{W \over Q}$$      Where, V = potential difference between two points
                   W = work done in moving charge
                   Q = quantity of charge moved.

ONE VOLT:

The potential difference between two points when 1 joule of work is done in moving 1 coulomb of charge from one point to another is called one volt.

$$1\,\,volt\,\,\, = \,\,\,{{1\,\,joule} \over {1\,\,coulomb}}$$

The condition necessary for flow of electric charge through a conductor:

  Maintaining a potential difference across the terminal points of the conductor.

AMMETER:

A device which is used for measuring electric current flowing in a circuit is called an ammeter.

VOLTMETER:

A device which is used for measuring potential difference between two points is called a voltmeter.

GALVANOMETER:

A device which is used for detecting the presence and direction of electric current flowing in a circuit is called a galvanometer.

ELECTRICAL CIRCUIT:

A continuous path consisting of conducting wires and other resistors between the terminals of a battery along which an electric current flows, is called an electric circuit.

CIRCUIT DIAGRAM:

A diagram, which indicates how different components in a circuit have been connected by using the electrical symbols for the components, is called a circuit diagram.

Circuit diagram showing one bulb connected to a cell, switch and Ammeter