CBSE Notes Class 10 Science Chapter 11 - Electricity

Electricity is a fundamental form of energy that powers everyday life, from lighting homes to running electronic devices. It explains how electric charges move, how current flows in a circuit, and how electrical energy is converted into useful work through simple laws and principles.

CBSE Notes Class 10 Science Chapter 11 – Electricity present these concepts in a structured, exam-oriented manner, covering electric current, potential difference, Ohm’s Law, resistance, electrical power, and numerical problem-solving techniques. These electricity class 10 notes, prepared strictly according to the latest syllabus, are part of comprehensive CBSE Notes Class 10 resources that help build strong conceptual clarity, enable quick revision, and support confident performance in board examinations.

1.0Download CBSE Notes for Class 10 Science Chapter 11: Electricity - Free PDF!!

Download Free CBSE Class 10 Science Chapter 11: Electricity Notes PDF to understand electric current, voltage, resistance, Ohm’s Law, electric circuits, and numericals. These concise, CBSE-aligned notes help in quick revision and scoring high in board exams.

2.0Electric Current and Circuit

It is the flow of  charge through a conductor. The electric current I is referred to as the charge Q passing through a point in a circuit per unit time.

I = Qt. Ampere is the SI  Unit of current(A).Current is a scalar quantity.

Electricity is categorised into:

Static Electricity: Concerns stationary charges.

Current Electricity: Involves moving charges.

Electric charge is a property of matter responsible for electric and magnetic effects. Coulomb is the practical  SI Unit of Electric Charge, and it is also a scalar quantity.

Properties of Electric Charge

• Like charges repel; unlike charges attract.
• Charge is conserved and additive.
• Charge is quantised, meaning it exists in discrete amounts.

3.0Circuits

A circuit is a closed loop that permits the flow of electric current. It typically includes components such as resistors, capacitors, and power sources.

4.0Electric Potential and Potential Difference

Electric Potential (V): The work done per unit positive charge to move it from infinity to a point in an electric field:  V=WQ0

Electric potential is measured in volts (V), where 1 Volt = 1 Joule/Coulomb (J/C). It is a scalar quantity and can be positive or negative.

                                                V = WQ0

Potential Difference-The work done to move a unit charge from one point to another in a circuit: V = WQ0

One volt is the potential difference that results when one joule of work is done to move one coulomb of charge between two points.

5.0Ohm’s Law

Ohm’s Law states that the current through a conductor is directly proportional to the potential difference across it, provided the temperature remains constant: 

V $\propto$ I

or V = RI

or V/I = R

Where, R = Resistance of the conductor which is a constant

SI Unit of Resistance: Ohm (Ω). 1 Ohm is the resistance when 1 Volt is applied, and 1 Ampere of current flows through the conductor.  

6.0Detailed CBSE Class 10 Science Chapter 11 – Key Notes

Electricity

(1) Static electricity, deals with charges at rest and phenomenon associated with them.

(2) Current electricity, deals with charges in motion and phenomenon associated with them.

Static electricity

The electricity developed on the surfaces of insulating bodies when rubbed against each other is called frictional electricity or static electricity.

Source of static electricity

When two substances are rubbed together, some electrons are removed from the atoms on the surface of one and transferred to the other. The substance which gains electrons becomes negatively charged and the one which loses electrons becomes positively charged.

Electric Charge

Electrical charge is a property of matter.

Properties Of Electric Charge

• Electric charge is a scalar quantity.
• Electric charge is measured in a unit 'Coulomb'.
• It can be of two types only: positive and negative
• Like charges repel each other while unlike charges attract each other.

Matter consists of tiny particles called atoms. Atoms contain particles called protons, neutrons and electrons.

• Neutrons - No electric charge.
• Protons - Positive electric charge
• Electrons - Negative electric charge.

Electric potential

Electric potential at a point A in an electric field is the work done per unit positive charge in transporting it from infinitely far away to the point A. (see figure)

V = W/Q₀

Electric potential is a scalar quantity.

Unit of electric potential

SI unit: Volt (V)

Definition of 1 volt in terms of electric potential: 1 volt is the electric potential at any point A when 1 joule work is done in moving a charge of 1 coulomb from infinity to the point A.

Potential difference

Potential difference between two points is defined as the work done in carrying a unit positive charge from one point to another point.

V = W/Q₀

Definition of 1 volt in terms of potential difference

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

If work done in moving a unit positive charge from point A to point B is zero, it means, potentials of point A and point B are same, i.e., VA = VB

Conductors

Conductors are 'materials which allow electric current to pass through them are conductors of electricity'.

Insulators

The substances which do not allow the electric current to flow through them are called insulators.

Current Electricity

Electric current

Electric current is a scalar quantity. Though, a direction is associated with electric current, still it is not considered as vector quantity because it does not obey the vector laws but obeys scalar laws of addition.

Unit of electric current

The electric current is expressed by a unit called ampere (A), named after the French scientist, Andre-Marie Ampere (1775-1836). Small quantities of current are expressed in milliampere (1mA = 10⁻³ A) or in microampere (1 μA = 10⁻⁶ A).

SI unit: Ampere

1 Ampere = 1 coulomb/sec = 1Cs⁻¹

Definition of 1 ampere

1 ampere is the electric current flowing through a conducting wire when 1 coulomb charge flows through it in 1 second.

Current carriers

The charged particles which flow in a particular direction to produce electric current are called 'current carriers'.

Flow of charge through a conductor

Measuring potential difference

Measuring potential difference across a resistor using a voltmeter.

Measuring current

Measuring electric current through a resistor using an ammeter.

Electric circuits

A continuous path which consists of various electric devices like bulb, tube light, resistors, etc.

Circuit elements

Electric resistance

The property of a material which offers opposition to the electric current and dissipates energy is called its 'electric resistance'.

R = V/I

SI unit : ohm (Ω)

1 ohm = 1 volt/ampere or 1 Ω = 1 V A⁻¹

Ohm's law

According to Ohm's law, 'the current through certain conductors is directly proportional to the potential difference between its ends at a constant temperature'.

I ∝ V
or V ∝ I
or V = IR
or R = V/I

Ohm's law is not a fundamental law, it is only an empirical law that holds approximately good for many substances particularly metals

Resistors

A physical device which has the principal characteristic of offering electric resistance is called 'resistor'.

Materials used for resistors

(1) Alloys like manganin, constantan, nichrome, etc.; used in wire wound resistors.

(2) Carbon resistors; compact and low cost.

(3) Aluminium or copper wires; low resistance conductors used to make connecting wires/electrical transmission lines.

R ∝ l

R ∝ 1/A

R = ρ l/A

Resistivity (specific resistance)

It is a characteristic property of a material rather than that of a particular specimen of a material. It depends on physical conditions such as temperature and pressure.

If l is 1 unit length and A is 1 square unit area, then, R = ρ

SI unit : ohm-meter (Ωm)

Effect of stretching of a wire on resistance

R₂ = n²R₁

Resistors in series

R = R₁ + R₂ + R₃ + ... + Rₙ

Resistors in parallel

1/R = 1/R₁ + 1/R₂ + 1/R₃ + ... + 1/Rₙ

Heating effect of electric current

If an electric circuit is purely resistive, that is, it consists of resistors only connected to a battery, the source energy gets dissipated entirely in the form of heat. This heating effect is utilised in devices such as electric geysers, electric heater, electric iron, etc

Electric power: The work done per unit time by a source of emf (like a battery) in order to maintain electric current in a circuit is called 'electric power'.

Heating effect of current

V = W/Q

W = Q × V ... (1) [∵ V = W/Q]

Thus, the power input to the circuit by the source is

P = W/t = (Q × V)/t = (Q/t) × V = I × V or P = VI

Joule's law of heating

H = I²Rt

According to Joule's law of heating, the heat produced in a resistor is directly proportional to the square of current for a given resistance, directly proportional to resistance for a given current, and directly proportional to the time for which the current flows through the resistor.

Applications of thermal effects of current

Electric bulb: The electric heating or joules heating is used in producing light in 'electric bulb'.

An electric bulb consists of a filament of a strong metal with high melting point such as 'tungsten' (melting point 3380 °C) sealed in a glass bulb. Most of the power consumed by the filament appears as heat, and a small part of it is converted into the form of light.

Electric fuse and its action: It is a safety device used to prevent the electric appliances against excessive electric currents.

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. Usually, a metallic conducting wire (fuse wire) made of Tin (25%) and Lead (75%) having low melting point is used. The fuse wire is usually encased in a cartridge of porcelain or similar material with metal ends.

7.0Benefits of CBSE Notes for Class 10 Science Chapter 11 - Electricity

• Formula and Derivation Recall: CBSE Notes often include important formulas and step-by-step derivations, aiding in quick memorisation and application.
• Diagrammatic Representation: Some notes include key diagrams related to electric circuits and their components, which are vital for understanding and scoring well.
• Practice Question Hints: Good notes might even provide hints or approaches to solving common types of numerical problems from the chapter.
• Reduced Stress: Having well-structured notes can reduce exam-related anxiety by making the CBSE Class 10 syllabus feel more manageable.
• Efficient Learning: You can learn and reinforce concepts more efficiently by focusing on the curated content in the notes.
• Personalised Learning: You can further customise existing notes with your own annotations, examples, and mnemonics to suit your learning style.

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