Electricity CBSE Class 10 Science Revision Notes Chapter 12


If you are thinking about how you will revise the whole chapter of Electricity before exams, askIITians online free revision notes are the best solution for you. These notes include all the concepts of the NCERT Class 10 Science Chapter 12 that will help you revise all the concepts of this chapter in just 20 minutes. Many times it gets tough to refer to the textbook and look for a topic while you study. If you have CBSE Class 10 revision notes by your side, you can easily look up the concept and do your classwork. You can also revise every topic before exams without reading the whole chapter from the textbook again. The diagrams and tables help in memorising the concepts of the chapter much better. 


Class 10 Electricity Chapter includes some basic concepts about charges and electricity that are important for higher studies, especially if you are going to prepare for JEE and NEET. The main concepts included in the Class 10 Revision Notes for Chapter 12 Electricity include current, potential difference, resistance, Ohm’s law, rheostat, resistivity, resistors in series and parallel combinations, the heating effect of electric current, Joule’s law, electric fuse, electric power, etc. Each of these topics is explained in pointwise format with the help of diagrams and tables. You can learn every topic of this chapter easily with our free revision notes for CBSE Class 10 Science Chapter Electricity. 


Free Revision Notes for CBSE Class 10 Science Chapter 12 Electricity 



Protons and electrons possess some charge. Protons have a positive charge. Electrons have a negative charge. Neutron does not possess any charge. Like charges repel each other and unlike charges attract each other.


Conductors and Insulators

Conductors are those materials in which electrons can move freely. All metals are conductors. Insulators do not have any free electrons to move. For example, wood and plastic.


Electric Current

The flow of electric charge is known as Electric Current. It is expressed in terms of the rate of flow of charges.

The SI unit of electric current is Ampere (A).

  • The direction of electric current is the same as the direction of positive charges and opposite to the direction of flow of negative charges.


Potential Difference

Work done per unit charge when taking charge from one point to another is known as the Potential Difference. The unit of potential difference is volt (V). 1V is defined as the potential difference between two points if 1 Joule of work is done to move 1-coulomb charge from one point to another.


Ohm’s law

The potential difference between the two points is directly proportional to the current, provided the temperature is constant.

V ∝ l

⇒ V = lR

R is a constant known as Resistance. The SI unit of resistance is the ohm (Ω)

Factors on which resistance of a conductor depends-

  • It is directly proportional to the length of the conductor.
  • Inversely proportional to the area of cross-section.
  • Directly proportional to the temperature.
  • Depends on the nature of the material.



Resistivity is the property of the material. The SI unit of resistivity is ohm-metre.

  • The resistivity of metals varies from 10-8 to 10-6.
  • The resistivity of insulators varies from 1012 to 1017
  • Copper and aluminium are used in electrical transmission due to their low resistivity.
    • Resistance = Resistivity * Length of Conductor/Cross-Sectional Area


Resistors in series

When two or more resistors are joined in series, then their total resistance is given by the formula-

RS = R1 + R2 + R3

The current will remain the same through all resistors. Total voltage is given by-

V = V1 + V2 + V3

Voltage across each resistor is given as –

V1 = lR1

V2 = lR2 [V1 + V2 + V3 = V]

V3 = lR3V = lR

⇒ V = lR1 + lR2 + lR3

lR = l(R1+ R2 + R3)

R = R1 + R2 + R3


Resistors in parallel

In this case, voltage is the same across each resistor and is equal to the applied voltage. The total current is given as-

V/R = V/R1 + V/R2 + V/R3

1/Rp = 1/R1 + 1/R2 + 1/R3


Advantages of Parallel Combination over Series Combination

If one component fails in a series combination, then the complete circuit is broken and no component can work properly. Different appliances need different currents. 


Heating effects of Electric Current

When charge Q moves against the potential difference V in time t, the amount of work is given by-


Joule’s Law of Heating

  • The heat produced in a resistor is directly proportional to the square root of the current.
  • It is also directly proportional to resistance for a given current.
  • Also, directly proportional to the time

H = l2 Rt


Practical Applications of the Heating Effect of Electric Current

  • The electric laundry iron, electric toaster, electric oven, electric kettle and electric heater are some of the familiar devices based on Joule’s heating.
  • Electric heating is also used to produce light in a bulb. The filament of an electric bulb is made up of tungsten because it has a very high melting point and also does not oxidise readily at a high temperature.
  • An electric fuse is a safety device to protect the electrical appliance from a short circuit. The fuse is placed in series with the device. It consists of a piece of wire made of a metal or an alloy of appropriate melting point, for example, aluminium, copper, iron, lead etc. If a current larger than the specified value flows through the circuit, the temperature of the fuse wire increases. This melts the fuse wire and breaks the circuit.


Electric Power

The rate at which electric energy is dissipated or consumed in an electric current. The SI unit of power is Watt.

P = Vl

⇒ P = l2 R = V2/R

The commercial unit of electric energy is a kilowatt-hour (KWh).


Class 10 Revision Notes for Science Chapter 12 Electricity FAQs



  • What are the benefits of CBSE Class 10 revision notes for Electricity? 

Revision notes for the Class 10 Electricity chapter are created by Science experts in an easy to understand format. Once you read these revision notes, there is no need to refer to your textbook again and again. These notes can help you revise the chapter in just 20 minutes. They include the latest syllabus of Class 10 Science. 


  • What are the important concepts in Class 10 CBSE Chapter 12 Electricity? 

The main concepts of this chapter that will help you in higher classes are potential difference, Ohm’s law, resistivity, resistors in parallel and series combinations, the heating effect of electric current, and power. You must use our free revision notes for Class 10 CBSE Chapter 12 Electricity to revise these concepts. 


  • How to prepare CBSE Class 10 Chapter 12 Electricity revision notes?

If you want to create your notes for this chapter you must have a thorough understanding of every topic. We recommend you read the NCERT chapter and underline all the key concepts or definitions. Write down those concepts in your language in pointwise format and create your notes. You can also seek help from our free revision notes. They are written in simplified language and cover all the points of the chapter. 


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