CBSE Class 10 Science — Magnetic Effects of Electric Current | Important Concept-Based Questions & Exam Tips

CBSE Class 10 Science: Magnetic Effects of Electric Current

Concept-Based Questions | Important Formulas | Diagrams | Revision Plan

Introduction

The chapter “Magnetic Effects of Electric Current” bridges the concepts of electricity and magnetism. It explains how electric current produces a magnetic field and how this interaction drives devices like motors and generators. For CBSE Class 10 students, understanding this chapter ensures full marks in numericals and application-based questions.

This blog presents concept-based questions, formulas, diagrams, and a 2-week revision plan to make your board preparation easier.

Key Concepts and Definitions

• Oersted’s Experiment: Current flowing through a wire creates a magnetic field around it.
• Right-Hand Thumb Rule: Thumb → Current, Fingers → Magnetic Field direction.
• Magnetic Field Lines: Imaginary lines that represent the magnetic field around a current-carrying conductor.
• Electromagnet: A temporary magnet made by passing current through a coil wrapped on a soft iron core.
• Electric Motor: Converts electrical energy into mechanical energy.
• Electric Generator: Converts mechanical energy into electrical energy.

Important Formulas

B = μ₀I / 2πr → Magnetic field due to a long straight conductor.

B = μ₀NI / L → Magnetic field inside a solenoid.

F = BIL → Force on a current-carrying conductor in a magnetic field.

Φ = B × A → Magnetic flux through an area A.

Concept-Based Questions and Model Answers

Q1: What did Oersted’s experiment prove?
Ans: It proved that electric current produces a magnetic field around it.

Q2: Explain the magnetic field pattern around a straight conductor.
Ans: The field lines form concentric circles around the wire, direction given by the right-hand thumb rule.

Q3: What happens when two parallel conductors carry current in the same direction?
Ans: They attract each other. If the currents are in opposite directions, they repel.

Q4: State Fleming’s Left-Hand Rule.
Ans: Stretch your thumb, forefinger, and middle finger of the left hand at right angles to each other: Forefinger → Field, Middle finger → Current, Thumb → Motion.

Q5: Why is a soft iron core used inside solenoids?
Ans: It increases magnetic field strength as soft iron has high magnetic permeability.

Q6: What is the role of split rings in a DC motor?
Ans: They reverse current direction every half rotation to keep the coil rotating continuously.

Applications of Magnetic Effects of Electric Current

• Electric Bell – Uses electromagnet to ring automatically.
• Magnetic Cranes – Lift heavy iron objects using electromagnets.
• Electric Motors – Convert electrical to mechanical energy.
• Generators – Produce electricity using mechanical rotation.

2-Week Smart Revision Plan

Week 1: Focus on theory and diagrams. Revise Oersted’s experiment, rules, and field lines. Practice 2 concept questions daily.

Week 2: Attempt past CBSE questions. Write one-page notes for formulas and applications. Take self-tests to boost retention.

Exam Tips for Full Marks

• Always draw neat and labelled diagrams.
• Use SI units in numericals — they carry marks.
• Mention the correct rule (Right-Hand Thumb or Fleming’s) in application questions.
• Answer in 3–4 crisp points — clear and concise.

Contact Information

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