Class 10 Science Chapter 11: Electricity – NCERT Solutions Notes Electricity is one of the most important Physics chapters in Class 10 Science. It explains electric current, potential difference, Ohm’s law, resistance, and electric power. It is highly numerical and scoring if concepts are clear. These notes are designed for NCERT-based understanding and exam revision. Key Concepts Electric Current Electric current is the flow of electric charge. Formula: I = Q / t Where: I = current, Q = charge, t = time Unit: Ampere (A) Electric Potential Difference It is the work done to move a unit charge between two points. Formula: V = W / Q Unit: Volt (V) Ohm’s Law At constant temperature, current is directly proportional to potential difference. Formula: V ∝ I V = IR Where R = resistance Resistance Resistance is the opposition offered to the flow of current. Factors affecting resistance: Length (directly proportional) Area of cross-section (inversely proportional) Material Temperature Resistivity Property of material that defines resistance. Formula: R = ρ L / A Unit: ohm-meter (Ωm) Series Combination of Resistors Current is same Resistance adds up Formula: R = R₁ + R₂ + R₃ Parallel Combination of Resistors Voltage is same Current divides Formula: 1/R = 1/R₁ + 1/R₂ + 1/R₃ Electric Power Rate of doing electrical work. Formula: P = VI P = I²R P = V²/R Unit: Watt (W) Electric Energy Energy consumed by electrical appliances. Unit: Joule (J) Kilowatt-hour (kWh) 1 kWh = 3.6 × 10⁶ J Heating Effect of Electric Current Heat produced due to resistance. Joule’s Law: H = I²Rt NCERT Important Questions (Concept Based) What is Ohm’s law? Relationship between voltage and current. Why does resistance increase with length? Because electrons face more collisions. What is electric power? Rate of electrical energy consumption. Important Numericals to Practice V = IR R series and parallel Power calculations Energy in kWh Important Diagrams to Revise Circuit diagram of Ohm’s law Series and parallel resistor connections Simple electric circuit Why this chapter is important This chapter is very important for exams and heavily numerical-based. It appears in: Numerical problems Circuit diagrams Conceptual questions NCERT exercises Final Revision Tip Focus on: Ohm’s law (most important) Series vs parallel Power formulas Unit conversions (kWh to Joule)