Class 10 Electricity Mind Map for Last Minute Board Revisions

Electricity is an important chapter in the Class 10 Science syllabus. This topic plays a key role for students preparing for the Science board exam 2026. Questions about electricity are frequently asked in the form of numericals, definitions, circuit-based problems, and reasoning questions. A clear understanding of this chapter helps students score well in the Science 10th class board exam 2026.

Learning electricity also helps students connect scientific concepts with daily life. Examples include the use of electric bulbs, heaters, fuses, and household appliances. Concepts like current, voltage, resistance, and power explain how these devices work. 

A mind map–based approach supports quick revision by organizing formulas, definitions, and diagrams in a connected and easy-to-recall format, which is especially useful during exam preparation.

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Class 10 Electricity Mind Map Series

Many students find the chapter Electricity challenging due to multiple formulas, circuit diagrams, and numerical problems. With the Science board exam 2026 approaching, recalling relations between current, voltage, resistance, and power can become difficult during last-minute revision. 

This mind map series breaks the chapter into connected concepts, formulas, and diagrams, helping students revise faster, improve accuracy in numericals, and reduce confusion before the Science 10th class board exam 2026.

What Is Electricity?

Electricity is the study of electric charge and its effects. It deals with how charge behaves at rest and in motion. Electricity is used in homes, industries, transport, and communication.

There are two main types of electricity:

• Static electricity

• Current electricity

Class 10 Science mainly focuses on current electricity.

Electric Charge (Q)

Electric charge is a fundamental property of matter, not a physical entity itself. It is a physical property that causes matter to experience a force (attraction or repulsion) when near other charged matter. All matter, composed of atoms with electrons, protons, and neutrons, inherently contains charge. Charge cannot exist without matter, and matter cannot exist without charge.

• SI Unit: The SI unit of charge is the Coulomb (C).

• Symbol: Charge is denoted by Q or q.

• Nature: It is a scalar quantity.

Quantization of Charge

Quantization signifies that electric charge exists in discrete, fixed packets, not continuous amounts. The term "quanta" refers to a fixed quantity. The smallest unit of charge freely found in nature is the charge of a single electron, whose value is 1.6 x 10⁻¹⁹ C. This elementary charge is the fundamental quantum of charge.

Common Units for Charge

• microcoulomb (μC): 1 μC = 10⁻⁶ C

• millicoulomb (mC): 1 mC = 10⁻³ C

Electric Current (I)

Electric current is the study of charge in motion, defined as the rate of flow of electric charge. It measures how much charge passes through a conductor per unit of time. (Consider two water pipes; the one with a stronger flow has a higher "water current.")

• Formula: I = Q / t (Current = Charge / Time)

• SI Unit: The SI unit of current is the Ampere (A).

• Definition of 1 Ampere: 1 Ampere is the flow of 1 Coulomb of charge through a conductor in 1 second.

• Nature: Current is a scalar quantity, as it does not obey vector algebra rules despite having a direction.

Common Units for Current

• microampere (μA): 1 μA = 10⁻⁶ A

• milliampere (mA): 1 mA = 10⁻³ A

Ammeter

An Ammeter is the device used to measure electric current in a circuit. It is always connected in series within the specific branch where current measurement is required.

Electric Circuit

A circuit provides the path through which electric current flows.

Potential Difference (V)

Potential difference, also called voltage, is the "push" that drives charge to flow in a circuit. Charges do not move spontaneously. Analogously, water flows from a higher to a lower level. Similarly, electric current flows from a point of higher potential (like a battery's positive terminal) to a point of lower potential (negative terminal) in the external circuit.

• Definition: Potential difference between two points is the work done to move a unit positive charge from one point to the other.

• Formula: V = W / Q (Potential Difference = Work Done / Charge)

• SI Unit: The SI unit is the Volt (V).

• Definition of 1 Volt: The potential difference is 1 Volt if 1 Joule of work is done in moving 1 Coulomb of charge between two points.

• Nature: It is a scalar quantity.

Voltmeter

A Voltmeter is the instrument used to measure potential difference (voltage) between two points in a circuit. It is always connected in parallel across the component whose voltage is to be measured.

Common Electrical Circuit Symbols

A basic electric circuit requires a device, conducting wires, an energy source (cell/battery), and a switch.

Ohm's Law

Ohm's Law describes the relationship between potential difference (V) and current (I). It states that the electric current flowing through a conductor is directly proportional to the potential difference across its ends, provided physical conditions like temperature remain constant.

• Mathematical Representation: V ∝ I, which leads to V = IR.

• Here, R is the constant of proportionality, known as Resistance.

Resistance (R)

Resistance is the property of a conductor that opposes the flow of electric current. This opposition arises from collisions between moving electrons and the atoms or ions within the conductor, causing energy loss as heat.

• SI Unit: The unit of resistance is the Ohm (Ω).

• From Ohm's Law, R = V / I.

• Nature: It is a scalar quantity.

VI and IV Graphs

For a conductor obeying Ohm's Law, a graph of V versus I is a straight line passing through the origin. The slope of the V-I graph (V on y-axis, I on x-axis) gives the resistance: Slope = ΔV / ΔI = R.

Factors Affecting Resistance

The resistance of a conductor depends on four key factors:

1. Length of the Conductor (L): Resistance is directly proportional to the length (R ∝ L). Longer wires offer more resistance.

2. Area of Cross-Section (A): Resistance is inversely proportional to the cross-sectional area (R ∝ 1/A). Thicker wires offer less resistance. (Memory Tip: To achieve low resistance and high current, use a "छोटी मोटी तार" (short and thick wire) – short length and large area minimize resistance.)

3. Nature of the Material: Different materials have an intrinsic property called resistivity (ρ), which determines their inherent resistance.

4. Temperature: For most conductors, resistance increases as temperature increases.

Combining length and area, the formula for resistance is: R = ρ (L/A).

Resistivity (ρ)

Resistivity is a fundamental material-dependent property that quantifies how strongly a material opposes current flow. It is the resistance of a conductor with unit length (1 m) and unit cross-sectional area (1 m²).

• SI Unit: The SI unit of resistivity is the Ohm-meter (Ω·m).

• Dependency: Resistivity depends only on the nature of the material and temperature.

Combination of Resistors

Resistors in a circuit can be combined in series or parallel configurations.

Heating Effect of Electric Current (Joule's Law of Heating)

This effect describes how electrical energy converts into heat when current flows through a resistor. Electrons, energized by a battery, collide with atoms within the conductor, causing their kinetic energy to dissipate as heat. This phenomenon is known as Joule's Law of Heating.

The SI unit for heat, a form of energy, is the Joule (J).

Formulas for Heat (H):

• H = V * I * t

• H = I² * R * t (Joule's Law)

• H = (V² / R) * t

Practical Applications of the Heating Effect

1. Heating Elements in Electrical Appliances

Appliances like electric heaters, irons, and geysers use a heating element, typically made of Nichrome wire (an alloy of Nickel and Chromium). Nichrome is chosen due to its high resistivity (ρ), which leads to high resistance (R) and, consequently, greater heat (H) generation, as H ∝ R.

2. The Incandescent Electric Bulb

An incandescent bulb produces light through the heating effect. Its filament is made of Tungsten (W), which has:

1. High Resistance: To generate significant heat and glow.

2. Very High Melting Point: Approximately 3380 °C, allowing it to reach incandescence without melting.
   The bulb is filled with an inert gas (e.g., Argon or Nitrogen) to prevent the hot filament from oxidizing.

3. The Electric Fuse

A fuse is a safety device protecting circuits from excessive current. It contains a fuse wire made from an alloy of Tin (Sn) and Lead (Pb). When the current exceeds a safe limit (overloading), the fuse wire melts, breaking the circuit and stopping the flow. 

(Memory Tip: Think of a fuse as a security guard for an electrical circuit. It sacrifices itself (by melting) to protect the valuable appliances from damage due to too much current.)

Comparative Structure: Bulb Filament vs. Fuse Wire

Electric Power

Electric Power is the rate at which electric energy is consumed or dissipated in an electric circuit, or the rate at which work is done. A more powerful circuit transfers more energy in less time.

• Basic Formula: Power (P) = Work Done (W) / Time (t) or Power (P) = Energy (E) / Time (t)

• SI Unit: The SI unit of power is the Watt (W).

Formulas for Electric Power (P):

• P = V * I

• P = I² * R

• P = V² / R

Energy (E) formulas can be derived by multiplying Power (P) by time (t), since E = P * t.

• E = V * I * t

• E = I² * R * t

• E = (V² / R) * t

Horsepower Conversion: 1 Horsepower (hp) = 746 Watts (W).

Commercial Unit of Electric Energy

For billing purposes, the commercial unit of electric energy is the kilowatt-hour (kWh). Your electricity bill reflects the number of kWh consumed.

• Conversion to Joules: 1 kWh = 3.6 x 10⁶ Joules (J).

Complete Formula Sheet Summary

Here is a consolidated list of key formulas from the chapter on Electricity:

1. Charge and Current

• Quantization of Charge: Q = n * e

• Electric Current: I = Q / t

2. Voltage, Resistance, and Ohm's Law

• Potential Difference (Voltage): V = W / Q

• Ohm's Law: V = I * R

• Resistance (material properties): R = ρ * (L / A)

• Slope of V-I graph: Slope = ΔV / ΔI = R

3. Resistors in Combination

• Series Combination: R_s = R₁ + R₂ + R₃ + …

• Parallel Combination: 1/R_p = 1/R₁ + 1/R₂ + 1/R₃ + …

4. Power and Energy (Heat)

• Power Basic Formula: P = E / t

• Power Formulas:

• P = V * I

• P = I² * R

• P = V² / R

• Energy Formulas:

• E = V * I * t

• E = I² * R * t

• E = (V² / R) * t

Summary of Units

• Current (I): Ampere (A)

• Charge (Q): Coulomb (C)

• Voltage (V): Volt (V)

• Work (W) / Energy (E): Joule (J)

• Power (P): Watt (W)

• Resistance (R): Ohm (Ω)

• Resistivity (ρ): Ohm-meter (Ω·m)

• Length (L): meter (m)

• Area (A): meter squared (m²)

• Commercial Unit of Energy: kilowatt-hour (kWh)