TEACHGYAN • CLASS 10 SCIENCE • NCERT 2026–27

Chapter 11: Electricity

Detailed Notes • Diagrams • Experiments • Competency • Board Practice

📖 Chapter Explanation

Electric current describes the rate of flow of electric charge. The chapter connects potential difference, resistance and current through Ohm’s law, then develops series/parallel combinations, heating effect and electrical power.

🧭 Concept Map

charge flow → current → potential difference → resistance → Ohm’s law → series/parallel → heating → power

🔬 Core Science

Ohm’s law: V=IR. Electrical power can be written as P=VI=I²R=V²/R. Electrical energy is power multiplied by time.

🖼️ Diagram / Visual Study

Cell → Switch → Resistors/Appliances → Return path | Series: one path | Parallel: multiple branches

Draw a clean labelled diagram showing direction/arrows, components and the scientific relationship involved.

💡 Worked/Applied Example

For a 6 Ω resistor connected to 12 V, I=V/R=2 A and P=VI=24 W. State units at every step.

⚠️ Common Errors

Do not confuse current, voltage and resistance. In series, current is the same through each resistor; in parallel, potential difference is the same across branches.

🧠 Concept-Based MCQs

Ohm’s law is: A) V=IR B) V=I/R C) R=VI D) P=IR
The SI unit of resistance is: A) volt B) ampere C) ohm D) watt
In a series circuit, the current is: A) different everywhere B) same through each component C) always zero D) equal to voltage
Electrical power is measured in: A) joule only B) watt C) ohm D) coulomb

Answer Key: 1-A, 2-C, 3-B, 4-B.

📊 Case-Based / Competency

A school replaces bulbs with LED fixtures. Students calculate current and power from the given ratings and compare energy use over a month.

Identify the scientific principle.
Represent the situation with a diagram/model.
Apply the relevant law or concept.
Interpret and verify the conclusion.

🔎 Extension Case

A classroom has several appliances with different power ratings. Students calculate current at a fixed voltage, identify a suitable circuit arrangement and estimate energy consumption.

🧪 Activity / Observation Corner

Plan a safe classroom observation or demonstration related to the chapter. Record the objective, materials, procedure, observation and inference. Follow teacher/laboratory safety instructions for any practical work.

🔥 HOTS & Board Challenge

Explain why the phenomenon occurs.
Predict what changes if one variable is altered.
Find and correct a plausible incorrect explanation.
Apply the concept to a real-life situation.

✍️ Exam Practice

Define the central concept.
Answer a diagram-based question.
Solve a numerical/application question.
Explain an experiment or real-life application.
Write a complete 5-mark answer with scientific reasoning.

📄 Practice Worksheet

5 concept checks
5 application questions
3 diagram-based questions
2 case-based questions
2 HOTS questions
1 board-style challenge

🎯 One-Minute Revision