What is Electric Charge

It is the basic property of matter

It causes attraction and repulsion in matter in presence of other matter

The amount of electricity contained in an object is called Electric Charge

It is denoted by Q.


What are Different Types of Charges

There are 2 types Of Charges

  • Positive Charge
  • Negative Charge


Important Property of Electric Charge

There are 2 important properties of Electric Charge

Unlike Charges Attract Each Other

So Positive Charge Attracts Negative Charge


Like Charges Repel Each other

(2 Positive Charges Repel each other  or 2 Negative Charges Attract Each Other)



What is Charge on Different Parts of Atom

We know that Atom is made up of Protons, Neutrons and Electrons

Parts Of Atom Charge
Protons They have Positive Charge
Electrons They have Negative Charge
Neutrons They have no Charge

No charge In the green balls in the image showing laws of attraction and repulsion


If an item has equal number of Protons and Electrons, they would cancel each other, and the item would have no Charge

If it has More Protons than Electrons, it is Positively Charged

If  is has More Electrons than Protons, it is Negatively Charged


What is Electric Current

It is the flow of Electric Charges in Conductor

It is the amount of Electric Charge flowing in a body in 1 Second

It is denoted by I.


Formula for Electric Current

Electric Current = Electric Charge/Time

I = Q/t


What is SI unit of Electric Current

It is measured in Ampere. It is denoted by A.


Electric Current = Electric Charge/Time


1 Ampere = 1 Coulomb/1 Second


What are Different Units of Electric Current?

It is measured in Ampere, Milliampere and Microampere



It is the SI Unit of Electric Current

It is named after French Scientist Andre Marie Ampere

As Electric current = Electric Charge/Time

So 1 Ampere = 1 Coulomb/1 Second

One ampere is defined as the current produced when a charge of 1 coulomb flows for 1 second.



It is smaller unit of Electric Current

1000 Milli Ampere = 1 Ampere

1 Milliampere = 1/1000 Ampere

1 Milliampere = 10 -3 Ampere

1 mA = 10 -3 A



It is even smaller unit of Electric Current

10,00,000 Miliampere = 1 Ampere

1 Milliampere = 1/1000000 Ampere

1 Microampere = 10 -6 Ampere

1 μA = 10 -6 A


Electric Current is flow of electrons(negatively charged particles)

Electric Current moves from negative Side of battery to positive Side of battery


How does Electric Current Flow in a Circuit Diagram

In Circuit Diagram, it is represented that

Electric Current flows From Positive end to negative end

This is because when electricity was first discovered, the existence of electrons was not known

However, in reality, it is the opposite.

Electric Current flows from Negative end of battery to positive end


How is Electric Current Measured?

it is measured with the help of Ammeter

This instrument is connected in a series in an electric circuit

In circuit diagram, it is denoted by



Q2 Page 200 - Define the unit of current.

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Q3 Page 200 - Calculate the number of electrons constituting one coulomb of charge.

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Example 12.1 - A current of 0.5 A is drawn by a filament of an electric bulb for 10 minutes. Find the amount of electric charge that flows through circuit.

View Answer


Question - A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross section of the filament in 16 seconds would be roughly

(a) 10 20

(b) 10 16

(c) 10 18

(d) 10 23

View Answer


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Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo