Board exam focus — Electricity (CBSE & HBSE)

Covers the quantitative aspects of electric circuits, Ohm's law, and energy consumption. CBSE emphasizes numerical problems on series/parallel circuits and power; HBSE focuses on basic definitions and circuit symbols.

Electric Current and Potential

1. Electric Current (I)

The rate of flow of electric charges (electrons) through a conductor.

• Formula: I = Q / t
• Unit: Ampere (A). 1 A = 1 Coulomb / 1 Second.
• Measuring Device: Ammeter (connected in series).

2. Electric Potential and Potential Difference (V)

Work done to move a unit charge from one point to another.

• Formula: V = W / Q
• Unit: Volt (V). 1 V = 1 Joule / 1 Coulomb.
• Measuring Device: Voltmeter (connected in parallel).

Ohm's Law and Resistance

1. Ohm's Law

At a constant temperature, the current (I) through a conductor is directly proportional to the potential difference (V) across its ends.

• V ∝ I => V = IR

2. Resistance (R)

The property of a conductor to resist the flow of charges.

• Unit: Ohm (Ω).

3. Factors affecting Resistance:

• Length (L): R ∝ L (Directly proportional).
• Area of Cross-section (A): R ∝ 1/A (Inversely proportional).
• Nature of Material.
• Formula: R = ρ(L/A) (where ρ is Resistivity).

Resistors in Series and Parallel

1. Resistors in Series

Same current flows through each resistor.

• Equivalent Resistance (Rs): Rs = R1 + R2 + R3 + ...

2. Resistors in Parallel

Same potential difference across each resistor.

• Equivalent Resistance (Rp): 1/Rp = 1/R1 + 1/R2 + 1/R3 + ...

Comparison:

• Series: Resistance increases. If one component fails, circuit breaks.
• Parallel: Resistance decreases. Independent control of appliances; widely used in domestic wiring.

Heating Effect and Electric Power

1. Joule's Law of Heating

Heat (H) produced in a resistor is directly proportional to the square of current, resistance, and time.

• H = I²Rt

2. Electric Power (P)

The rate at which electric energy is consumed.

• P = VI = I²R = V² / R
• Unit: Watt (W).

3. Commercial Unit of Energy

Kilowatt-hour (kWh) or 'Unit'.

• 1 kWh = 3.6 × 10⁶ Joules.

Frequently asked questions

Are these Electricity notes free?

Yes — the Electricity notes for Science (Class 10) on Siksha Sarovar are completely free to read, with no account required.

Do these notes follow CBSE and HBSE?

Yes. The Electricity notes are NCERT-aligned and include guidance for both CBSE and Haryana Board (HBSE), with important questions and MCQs for revision.

What does the Electricity chapter cover?

Concept explanations, key formulas and definitions, fully solved examples and board-pattern practice questions for Electricity.