Electricity Class 10 Notes CBSE – Chapter 11, Formulas, Diagrams, Numericals & Important Questions

Electricity is one of the most important chapters in Class 10 Science. This chapter explains how electric current flows in a circuit, how voltage and resistance control the flow of current, why resistors are connected in series or parallel, how electric heating works, and how electrical energy is calculated in daily life.

In the latest NCERT Class 10 Science textbook, this chapter is Chapter 11: Electricity. However, many students still search for it as Class 10 Science Chapter 12 Electricity Notes because older resources used that numbering. Both search terms refer to the same Electricity chapter.

These Electricity Class 10 Notes include chapter overview, definitions, formulas, circuit symbols, diagrams, Ohm’s law, resistance, resistivity, series and parallel combinations, heating effect of electric current, electric power, solved numericals, important questions, MCQs, assertion-reason questions, case-study questions and FAQs.

Electricity Class 10 Chapter Overview

Download Class 10 Electricity Notes PDF

Students can download the Class 10 Electricity Notes PDF to revise all important concepts, formulas, circuit diagrams, solved numericals, and exam-based questions in one place. This PDF is useful for quick revision before school tests and CBSE board exams. It covers Ohm’s law, resistance, series and parallel circuits, heating effect, electric power, and important formulas in a simple, student-friendly format.

What is Electricity?

Electricity is a form of energy produced due to the movement of electric charges. In metallic wires, these moving charges are mainly electrons.

Electricity is useful because it can be converted into many other forms of energy.

Electricity is used in homes, schools, hospitals, industries, transport, communication and many modern devices.

Electric Charge

Electric charge is a basic property of matter because of which electric forces and electric current are produced.

There are two types of electric charges:

1. Positive charge
2. Negative charge

Like charges repel each other, while unlike charges attract each other.

The SI unit of electric charge is coulomb, represented by C.

Important Points

One electron has a charge of:

1.6 × 10⁻¹⁹ C

One coulomb of charge contains approximately:

6 × 10¹⁸ electrons

Electric Current Class 10

Electric current is the rate of flow of electric charge through a conductor.

In simple words, when charges move through a wire, electric current flows.

Formula of Electric Current

I = Q/t

Where:

SI Unit of Electric Current

The SI unit of electric current is ampere, written as A.

One ampere current flows when one coulomb of charge passes through a conductor in one second.

1 A = 1 C/s

Smaller Units of Current

Direction of Electric Current

In a metallic conductor, electrons move from the negative terminal to the positive terminal.

However, the conventional direction of electric current is taken from the positive terminal to the negative terminal.

Electric Circuit

An electric circuit is a continuous and closed path through which electric current flows.

A simple electric circuit may contain:

• Cell or battery
• Connecting wires
• Switch or plug key
• Bulb or resistor
• Ammeter
• Voltmeter

Closed Circuit

A circuit is called a closed circuit when the path is complete and current can flow through it.

Open Circuit

A circuit is called an open circuit when the path is broken and current cannot flow through it.

For example, when a switch is turned off, the circuit becomes open and the bulb does not glow.

Circuit Symbols Class 10

Circuit diagrams are drawn using standard electrical symbols. These symbols make circuits easy to understand and help students draw neat diagrams in exams.

Explanation

When the switch is closed, the circuit becomes complete and current flows through the bulb. Due to the flow of current, the bulb glows.

When the switch is open, the circuit becomes incomplete and the bulb does not glow.

In a closed circuit, the switch is closed. The path is complete, so current flows and the bulb glows.

Image alt text: Open and closed circuit diagram Class 10 Electricity.

Potential Difference Class 10

Potential difference is the work done in moving a unit positive charge from one point to another point in an electric circuit.

In simple words, potential difference is the electrical pressure that pushes charges through a circuit.

It is also called voltage.

Formula of Potential Difference

V = W/Q

Where:

SI Unit of Potential Difference

The SI unit of potential difference is volt, represented by V.

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

1 V = 1 J/C

Device Used to Measure Potential Difference

A voltmeter is used to measure potential difference.

It is connected in parallel across the component.

Difference Between Current and Potential Difference

Ammeter and Voltmeter Connection Diagram

An ammeter is connected in series because it measures the current flowing through the circuit.

A voltmeter is connected in parallel because it measures the potential difference across a component.

Important Points

• Ammeter is connected in series.
• Voltmeter is connected in parallel.
• Ammeter has very low resistance.
• Voltmeter has very high resistance.

Image alt text: Ammeter in series and voltmeter in parallel circuit diagram Class 10.

Ohm’s Law Class 10

Ohm’s law gives the relationship between potential difference, current and resistance.

Statement of Ohm’s Law

According to Ohm’s law, the potential difference across the ends of a conductor is directly proportional to the current flowing through it, provided the temperature remains constant.

Mathematical Form

V ∝ I

Therefore:

V/I = constant

This constant is called resistance.

So:

V = IR

Where:

Ohm’s Law Formula

V = IR

Other forms:

I = V/R

R = V/I

Ohm’s Law Circuit Diagram

To verify Ohm’s law, a circuit is made using a battery, key, rheostat, ammeter, resistor and voltmeter.

Explanation

In this circuit:

• The battery supplies current.
• The key is used to open or close the circuit.
• The rheostat changes the current in the circuit.
• The ammeter measures current.
• The voltmeter measures potential difference across the resistor.
• The resistor is the conductor for which Ohm’s law is verified.

By changing the rheostat, different values of current and potential difference are recorded. A graph is then plotted between potential difference and current.

Image alt text: Ohm’s law experiment circuit diagram Class 10 with battery key rheostat ammeter resistor and voltmeter.

V-I Graph for Ohm’s Law

For an ohmic conductor, the graph between potential difference and current is a straight line passing through the origin.

Explanation

The straight-line graph shows that potential difference is directly proportional to current.

Therefore:

V ∝ I

So:

V = IR

If V is taken on the y-axis and I is taken on the x-axis, then:

Slope of V-I graph = Resistance

A steeper line means greater resistance.

Image alt text: V-I graph for Ohm’s law Class 10 showing straight line through origin.

Resistance Class 10

Resistance is the property of a conductor by which it opposes the flow of electric current.

A conductor with low resistance allows current to flow easily.

A conductor with high resistance opposes the flow of current.

SI Unit of Resistance

The SI unit of resistance is ohm, represented by Ω.

One ohm is the resistance of a conductor when a potential difference of 1 V produces a current of 1 A.

1 Ω = 1 V/A

Formula of Resistance

From Ohm’s law:

R = V/I

Where:

Factors Affecting Resistance of a Conductor

The resistance of a conductor depends on:

1. Length of the conductor
2. Area of cross-section
3. Nature of material
4. Temperature

1. Length of Conductor

Resistance is directly proportional to length.

R ∝ l

If the length of a wire increases, its resistance also increases.

A longer wire offers more opposition to the flow of current.

2. Area of Cross-Section

Resistance is inversely proportional to area of cross-section.

R ∝ 1/A

If the wire is thicker, its resistance is less.

If the wire is thinner, its resistance is more.

3. Nature of Material

Different materials have different resistances.

For example:

• Copper has low resistance, so it is used in electric wiring.
• Nichrome has high resistance, so it is used in heating elements.
• Rubber has very high resistance, so it is used as an insulator.

4. Temperature

In most metallic conductors, resistance increases when temperature increases.

Resistance Depends on Length and Area Diagram

Resistance of a wire depends on its length and area of cross-section.

Long Wire Has More Resistance

Short wire: ─────────Long wire: ─────────────────────────

A longer wire offers more resistance because electrons have to travel through a longer path.

Thick Wire Has Less Resistance

Thin wire: ─────────Thick wire: ═════════

A thick wire has a larger area of cross-section, so it offers less resistance.

Formula

R = ρl/A

This means:

• Resistance increases when length increases.
• Resistance decreases when area of cross-section increases.
• Resistance depends on the material of the conductor.

Resistivity Class 10

Resistivity is the resistance offered by a conductor of unit length and unit area of cross-section.

It is represented by the Greek letter ρ, called rho.

Formula of Resistance in Terms of Resistivity

R = ρl/A

Where:

From this formula:

ρ = RA/l

SI Unit of Resistivity

The SI unit of resistivity is:

ohm metre, Ω m

Difference Between Resistance and Resistivity

Why are Alloys Used in Heating Devices?

Alloys such as nichrome are used in heating devices like electric irons, heaters and toasters because:

1. They have high resistivity.
2. They can produce more heat.
3. They do not oxidise easily at high temperature.
4. They can withstand high temperature without melting quickly.

That is why heating elements are usually made of alloys rather than pure metals.

Combination of Resistors Class 10

Resistors can be connected in two main ways:

1. Series combination
2. Parallel combination

These combinations are important for understanding household circuits, electrical appliances and exam numericals.

Series Combination of Resistors

In a series combination, resistors are connected end to end in a single path.

The same current flows through every resistor.

Properties of Series Combination

1. Same current flows through all resistors.
2. Potential difference is divided among the resistors.
3. Total resistance is equal to the sum of individual resistances.
4. Equivalent resistance is greater than each individual resistance.
5. If one resistor or component fails, the whole circuit breaks.

Formula for Series Combination

If three resistors R₁, R₂ and R₃ are connected in series, then equivalent resistance is:

Rs = R₁ + R₂ + R₃

For more resistors:

Rs = R₁ + R₂ + R₃ + ...

Example

If resistors of 2 Ω, 3 Ω and 5 Ω are connected in series, then:

Rs = 2 + 3 + 5

Rs = 10 Ω

So, the equivalent resistance is 10 Ω.

Disadvantage of Series Circuit

Series arrangement is not used in household wiring because:

• If one appliance stops working, the whole circuit breaks.
• Different appliances need different currents.
• Appliances cannot be switched on or off independently.

Image alt text: Series combination of resistors Class 10 circuit diagram.

Parallel Combination of Resistors

In a parallel combination, resistors are connected between the same two points.

The potential difference across each resistor remains the same.

Properties of Parallel Combination

1. Potential difference remains the same across all resistors.
2. Current is divided among different branches.
3. Equivalent resistance is less than the smallest individual resistance.
4. If one branch fails, other branches continue to work.
5. Appliances can be switched on or off independently.

Formula for Parallel Combination

If three resistors R₁, R₂ and R₃ are connected in parallel, then:

1/Rp = 1/R₁ + 1/R₂ + 1/R₃

For two resistors:

Rp = R₁R₂ / (R₁ + R₂)

Example

If two resistors of 4 Ω and 6 Ω are connected in parallel:

Rp = R₁R₂ / (R₁ + R₂)

Rp = 4 × 6 / (4 + 6)

Rp = 24/10

Rp = 2.4 Ω

So, the equivalent resistance is 2.4 Ω.

Difference Between Series and Parallel Combination

Why are Household Appliances Connected in Parallel?

Household appliances are connected in parallel because:

1. Each appliance gets the same voltage.
2. Each appliance can work independently.
3. If one appliance is switched off, others keep working.
4. Appliances can draw current according to their resistance and power rating.
5. Fault in one appliance does not stop the whole circuit.

For example, if a bulb and a fan are connected in parallel, switching off the bulb does not stop the fan.

Explanation

In this arrangement:

• Each appliance gets the same voltage.
• Each appliance has a separate switch.
• If one appliance is switched off, the others continue working.
• If one appliance is damaged, the whole circuit does not stop.

Heating Effect of Electric Current

When electric current flows through a conductor, electrical energy is converted into heat energy.

This is called the heating effect of electric current.

For example:

• An electric iron becomes hot.
• An electric heater produces heat.
• A bulb filament becomes hot and glows.
• A fuse wire melts when excessive current flows.

Explanation

The heating coil is usually made of nichrome because nichrome has high resistance and can become very hot without melting easily.

This principle is used in:

• Electric heater
• Electric iron
• Electric toaster
• Electric kettle
• Geyser

Image alt text: Heating effect of electric current diagram Class 10 with nichrome heating coil.

Joule’s Law of Heating Class 10

Joule’s law of heating gives the amount of heat produced in a conductor when current flows through it.

Formula

H = I²Rt

Where:

Statement of Joule’s Law

Heat produced in a resistor is:

1. Directly proportional to the square of current
2. Directly proportional to resistance
3. Directly proportional to time

So:

H ∝ I²
H ∝ R
H ∝ t

Therefore:

H = I²Rt

Important Point

Current has the greatest effect on heat production because heat is proportional to the square of current.

If current becomes double, heat becomes four times.

Applications of Heating Effect of Electric Current

1. Electric Iron

An electric iron contains a heating element made of high-resistance alloy. When current passes through it, heat is produced.

2. Electric Heater

Electric heaters use coils made of nichrome. Nichrome has high resistance and produces a large amount of heat.

3. Electric Toaster

A toaster converts electrical energy into heat energy to toast bread.

4. Electric Kettle

An electric kettle uses a heating element to heat water.

5. Electric Fuse

A fuse is a safety device. It melts and breaks the circuit when excessive current flows.

6. Electric Bulb

In an electric bulb, the filament becomes hot and emits light.

Electric Fuse Class 10

An electric fuse is a safety device used to protect electrical circuits and appliances from excessive current.

It is made of a wire having low melting point.

How Does a Fuse Work?

When excessive current flows through a circuit, the fuse wire becomes very hot due to the heating effect of current. It melts and breaks the circuit. This stops the current and protects the appliance.

Fuse is Connected in Series

A fuse is always connected in series with the live wire so that it can stop the entire current when there is an overload.

Important Points

• Fuse is connected in series.
• Fuse wire has low melting point.
• Fuse works on the heating effect of electric current.
• Fuse protects appliances from overload and short circuit.

Image alt text: Electric fuse circuit diagram Class 10 showing fuse connected in series.

Electric Power Class 10

Electric power is the rate at which electrical energy is consumed or dissipated in an electric circuit.

Formula of Electric Power

P = VI

Using Ohm’s law, we also get:

P = I²R

P = V²/R

Where:

SI Unit of Electric Power

The SI unit of electric power is watt, represented by W.

One watt is the power consumed when a current of 1 A flows through a device at a potential difference of 1 V.

1 W = 1 V × 1 A

Larger Unit of Power

1 kilowatt = 1000 watt

1 kW = 1000 W

Formula

P = VI

Other formulas:

P = I²R

P = V²/R

Image alt text: Electric power Class 10 diagram showing conversion of electrical energy into heat light and motion.

Electrical Energy Class 10

Electrical energy is the total energy consumed by an electrical device.

Formula

E = Pt

Where:

If power is in watt and time is in second, energy is in joule.

If power is in kilowatt and time is in hour, energy is in kilowatt hour.

Commercial Unit of Electrical Energy

The commercial unit of electrical energy is kilowatt hour, written as kWh.

It is commonly called one unit of electricity.

Conversion

1 kWh = 1000 W × 3600 s

1 kWh = 3.6 × 10⁶ J

Meaning of 1 kWh

One kilowatt hour is the energy consumed by an appliance of power 1 kW when it is used for 1 hour.

Example:

A 1000 W heater used for 1 hour consumes:

1 kWh = 1 unit

Electricity Class 10 All Formulas

Important Units in Electricity Class 10

Solved Numericals on Electricity Class 10

Numerical 1: Current and Charge

A current of 0.5 A flows through a bulb for 10 minutes. Find the charge flowing through the circuit.

Given:

I = 0.5 A
t = 10 minutes = 10 × 60 = 600 s

Formula:

Q = It

Solution:

Q = 0.5 × 600
Q = 300 C

Answer: The charge flowing through the circuit is 300 C.

Numerical 2: Finding Current

A charge of 120 C flows through a wire in 2 minutes. Find the current.

Given:

Q = 120 C
t = 2 minutes = 120 s

Formula:

I = Q/t

Solution:

I = 120/120
I = 1 A

Answer: The current is 1 A.

Numerical 3: Potential Difference

How much potential difference is required to do 240 J of work in moving 40 C of charge?

Given:

W = 240 J
Q = 40 C

Formula:

V = W/Q

Solution:

V = 240/40
V = 6 V

Answer: The potential difference is 6 V.

Numerical 4: Ohm’s Law

A current of 2 A flows through a resistor of 5 Ω. Find the potential difference across the resistor.

Given:

I = 2 A
R = 5 Ω

Formula:

V = IR

Solution:

V = 2 × 5
V = 10 V

Answer: The potential difference is 10 V.

Numerical 5: Resistance

A potential difference of 12 V is applied across a resistor. If the current flowing through it is 3 A, find its resistance.

Given:

V = 12 V
I = 3 A

Formula:

R = V/I

Solution:

R = 12/3
R = 4 Ω

Answer: The resistance is 4 Ω.

Numerical 6: Series Combination

Three resistors of 2 Ω, 4 Ω and 6 Ω are connected in series. Find the equivalent resistance.

Given:

R₁ = 2 Ω
R₂ = 4 Ω
R₃ = 6 Ω

Formula:

Rs = R₁ + R₂ + R₃

Solution:

Rs = 2 + 4 + 6
Rs = 12 Ω

Answer: The equivalent resistance is 12 Ω.

Numerical 7: Parallel Combination

Two resistors of 6 Ω and 3 Ω are connected in parallel. Find the equivalent resistance.

Given:

R₁ = 6 Ω
R₂ = 3 Ω

Formula:

Rp = R₁R₂/(R₁ + R₂)

Solution:

Rp = 6 × 3 / (6 + 3)
Rp = 18/9
Rp = 2 Ω

Answer: The equivalent resistance is 2 Ω.

Numerical 8: Heating Effect

An electric iron of resistance 20 Ω takes a current of 5 A. Calculate the heat produced in 30 seconds.

Given:

R = 20 Ω
I = 5 A
t = 30 s

Formula:

H = I²Rt

Solution:

H = 5² × 20 × 30
H = 25 × 20 × 30
H = 15000 J

Answer: Heat produced is 15000 J.

Numerical 9: Electric Power

An electric bulb is connected to a 220 V supply and draws a current of 0.5 A. Find the power of the bulb.

Given:

V = 220 V
I = 0.5 A

Formula:

P = VI

Solution:

P = 220 × 0.5
P = 110 W

Answer: The power of the bulb is 110 W.

Numerical 10: Electrical Energy

A 1000 W heater is used for 2 hours. Calculate the energy consumed in kWh.

Given:

P = 1000 W = 1 kW
t = 2 h

Formula:

E = Pt

Solution:

E = 1 × 2
E = 2 kWh

Answer: Energy consumed is 2 kWh, or 2 units.

Numerical 11: Electricity Bill

A refrigerator rated 400 W is used for 8 hours per day for 30 days. If the cost of electricity is ₹6 per unit, find the total cost.

Given:

Power = 400 W = 0.4 kW
Time per day = 8 h
Number of days = 30
Cost per unit = ₹6

Formula:

Energy = Power × Time

Solution:

Total time = 8 × 30 = 240 h

Energy = 0.4 × 240
Energy = 96 kWh

Cost = 96 × 6
Cost = ₹576

Answer: The total cost is ₹576.

Numerical 12: Power Using Resistance

Find the power consumed by a resistor of 10 Ω when a current of 2 A flows through it.

Given:

R = 10 Ω
I = 2 A

Formula:

P = I²R

Solution:

P = 2² × 10
P = 4 × 10
P = 40 W

Answer: Power consumed is 40 W.

Numerical 13: Resistivity

A wire of resistance 10 Ω has length 2 m and area of cross-section 0.5 m². Find its resistivity.

Given:

R = 10 Ω
l = 2 m
A = 0.5 m²

Formula:

ρ = RA/l

Solution:

ρ = 10 × 0.5 / 2
ρ = 5/2
ρ = 2.5 Ω m

Answer: Resistivity is 2.5 Ω m.

Numerical 14: Work Done

A potential difference of 12 V is applied to move 5 C charge. Find the work done.

Given:

V = 12 V
Q = 5 C

Formula:

W = VQ

Solution:

W = 12 × 5
W = 60 J

Answer: Work done is 60 J.

Numerical 15: Heat Produced When Current Doubles

A current I produces heat H in a resistor. If the current is doubled, what will be the new heat produced in the same time?

Formula:

H = I²Rt

If current becomes 2I:

New heat = (2I)²Rt
New heat = 4I²Rt
New heat = 4H

Answer: The heat produced becomes four times.

Common Mistakes in Electricity Numericals

Practical-Based Questions: Electricity Class 10

CBSE practicals related to Electricity include:

1. Studying the relation between potential difference and current
2. Plotting a graph between V and I
3. Determining equivalent resistance of resistors in series and parallel

Experiment: To Verify Ohm’s Law

Aim

To study the relation between potential difference across a resistor and current through it, and to verify Ohm’s law.

Apparatus

• Battery
• Resistor or nichrome wire
• Ammeter
• Voltmeter
• Rheostat
• Plug key
• Connecting wires

Procedure

1. Connect the circuit using a resistor, ammeter, voltmeter, battery, key and rheostat.
2. Close the key and note the readings of ammeter and voltmeter.
3. Change the current using the rheostat.
4. Record different values of current and potential difference.
5. Plot a graph between V and I.

Observation Table

Result

The ratio V/I remains constant for a given resistor at constant temperature.

Therefore, Ohm’s law is verified.

Graph

The V-I graph is a straight line passing through the origin.

NCERT-Based Important Questions

Very Short Answer Questions

1. Define electric current.
2. What is the SI unit of charge?
3. What is the SI unit of current?
4. Define one ampere.
5. What is potential difference?
6. What is the SI unit of resistance?
7. What is the commercial unit of electrical energy?
8. What is the formula of electric power?
9. What is the formula of Joule’s law of heating?
10. Why is an ammeter connected in series?

Short Answer Questions

1. State Ohm’s law.
2. Define resistance and write its SI unit.
3. What are the factors on which resistance of a conductor depends?
4. What is resistivity? Write its SI unit.
5. Why are alloys used in heating devices?
6. Why is tungsten used in electric bulb filaments?
7. Why is a voltmeter connected in parallel?
8. Why are household appliances connected in parallel?
9. What is the difference between series and parallel combination?
10. What is the heating effect of electric current?

Long Answer Questions

1. Explain Ohm’s law with formula and graph.
2. Derive the formula for equivalent resistance in series.
3. Derive the formula for equivalent resistance in parallel.
4. Explain Joule’s law of heating and write its applications.
5. Explain electric power and derive P = VI, P = I²R and P = V²/R.
6. Explain the working of an electric fuse.
7. Compare series and parallel circuits.
8. Explain the factors affecting resistance of a conductor.

MCQs on Electricity Class 10

1. The SI unit of electric current is:

A. volt
B. ampere
C. ohm
D. coulomb

Answer: B. ampere

2. The formula of Ohm’s law is:

A. V = IR
B. I = QR
C. R = IQ
D. V = Q/t

Answer: A. V = IR

3. An ammeter is connected:

A. in parallel
B. in series
C. either series or parallel
D. across the resistor only

Answer: B. in series

4. The commercial unit of electrical energy is:

A. watt
B. joule
C. kilowatt hour
D. volt

Answer: C. kilowatt hour

5. If two resistors are connected in parallel, the equivalent resistance is:

A. greater than both resistors
B. equal to the sum of resistors
C. less than the smallest resistor
D. always zero

Answer: C. less than the smallest resistor

6. Joule’s law of heating is:

A. H = IRt
B. H = I²Rt
C. H = VIt²
D. H = R/t

Answer: B. H = I²Rt

7. The SI unit of resistance is:

A. ampere
B. volt
C. ohm
D. watt

Answer: C. ohm

8. A voltmeter is connected:

A. in series
B. in parallel
C. only with ammeter
D. only with battery

Answer: B. in parallel

Assertion-Reason Questions

Question 1

Assertion: Household appliances are connected in parallel.
Reason: In parallel combination, each appliance gets the same potential difference.

Answer: Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

Question 2

Assertion: A fuse is connected in series with the circuit.
Reason: A fuse must stop the entire current when excessive current flows.

Answer: Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

Question 3

Assertion: The resistance of a wire increases when its length increases.
Reason: Resistance is directly proportional to the length of the conductor.

Answer: Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

Case Study Question on Electricity

Read the passage and answer the questions.

A student connects three resistors of 2 Ω, 4 Ω and 6 Ω in series with a 12 V battery. The same current flows through all three resistors. The total resistance of the circuit is the sum of the three resistances.

Questions

1. What is the equivalent resistance of the circuit?
2. What current flows through the circuit?
3. Is the current same or different in all resistors?
4. What happens to total resistance in series combination?

Answers

1. Equivalent resistance = 2 + 4 + 6 = 12 Ω
2. Current = V/R = 12/12 = 1 A
3. The current is the same in all resistors.
4. Total resistance increases in series combination.

One-Page Revision Notes: Electricity Class 10

Key Definitions

Most Important Formulas

Important Exam Points

• Ammeter is connected in series.
• Voltmeter is connected in parallel.
• Current is same in series combination.
• Voltage is same in parallel combination.
• Series resistance is greater than individual resistances.
• Parallel resistance is less than the smallest resistance.
• Household wiring uses parallel combination.
• Fuse works on the heating effect of current.
• Commercial unit of electrical energy is kWh.
• One unit of electricity means one kW

Electricity Class 10 is an important Physics chapter for CBSE board exams. The chapter explains electric current, potential difference, Ohm’s law, resistance, resistivity, series and parallel combination of resistors, heating effect of electric current, electric power and electrical energy.

For scoring well, students should focus on formulas, units, circuit diagrams, V-I graph, series-parallel numericals, Joule’s law, electric power and electricity bill questions. Regular practice of solved numericals and important questions can make this chapter much easier and help students perform better in exams.