NCERT Solutions for Class 10 Science Chapter 11 Electricity

Short Note:

• Electric Current (I): The rate of flow of electric charges per unit time through a conductor cross-section (I = Q / t). Its SI unit is Ampere (A).

• Electric Circuit: A continuous and closed path along which electric current flows.

• Ammeter: An instrument used to measure electric current, always connected in series in a circuit.

Short Note:

• Potential Difference (V): The work done to move a unit positive charge from one point to another in an electric circuit (V = W / Q). Its SI unit is Volt (V).

• Voltmeter: Device used to measure potential difference, connected in parallel across points.

• 1 Volt is defined as 1 Joule of work done in moving a charge of 1 Coulomb from one point to another.

Short Note:

• Ohm's Law: At constant temperature, electric current (I) flowing through a metallic conductor is directly proportional to potential difference (V) across its ends (V = IR).

• Resistance (R): Property of a conductor to oppose the flow of electric current. SI unit: Ohm (Ω).

• Factors Affecting Resistance: Resistance depends directly on length (L), inversely on cross-sectional area (A), temperature, and nature of material (R = ρL / A, where ρ is resistivity).

Short Note:

• Series Combination: Resistors connected end-to-end. Total resistance R_s = R₁ + R₂ + R₃. Current remains constant across all resistors.

• Parallel Combination: Resistors connected across common nodes. Total resistance 1 / R_p = 1 / R₁ + 1 / R₂ + 1 / R₃. Potential difference remains constant across all branches.

Short Note:

• Joule's Law of Heating: Heat produced in a resistor is proportional to the square of current, resistance, and time duration (H = I²Rt).

• Electric Power (P): Rate at which electrical energy is consumed (P = VI = I²R = V² / R). SI unit: Watt (W).

• Commercial Unit: Kilowatt-hour (kWh). 1 kWh = 3.6 × 10⁶ Joules.