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Important Questions: CBSE Class 10 Science Chapter 12 Magnetic Effects of Electric Current

Magnetic Effects of Electric Current is among the highest-scoring chapters in CBSE Class 10 Science if you master the question patterns. The 2024 and 2025 board papers allocated 6-7 marks to this chapter through a mix of MCQs, diagram-based questions, numerical problems and one long-answer or case-based question. Topics like Fleming's rules, electromagnetic induction, and the working of electric motor and generator appear almost every year. This question bank mirrors actual CBSE exam style with model answers.

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Key takeaways

✓Chapter 12 Magnetic Effects of Electric Current carries 5-7 marks in CBSE Class 10 Science board exam, with questions typically split between MCQs and descriptive answers.
✓Fleming's Left Hand Rule and Right Hand Rule are frequently tested through diagram-based 3-mark questions requiring clear labelling and direction identification.
✓Electromagnetic induction concept appears in at least one 5-mark question every year, often combined with AC generator working principle.
✓Numerical problems on magnetic field strength around current-carrying conductors and solenoids appear regularly in 2-mark and 3-mark formats.
✓Domestic electric circuit questions linking fuse, earthing and short-circuit prevention carry consistent weightage and require practical understanding.
✓Case-based questions introduced from 2021 onwards test application of motor or generator principles in real-life scenarios worth 4-5 marks.
✓Diagrams earn 1-2 marks and must include proper direction arrows, clear labels and neat presentation to secure full credit.

Chapter Overview and Marks Weightage in CBSE Board Exam

Chapter 12 Magnetic Effects of Electric Current forms part of Unit V: Effects of Current in the CBSE Class 10 Science syllabus. The chapter typically contributes 5-7 marks to the 80-mark theory paper. The 2024 CBSE Class 10 Science paper featured one 3-mark question on Fleming's Left Hand Rule, one 2-mark numerical on magnetic field around a solenoid, two MCQs worth 1 mark each, and one 5-mark case study linking electromagnetic induction with real-world applications. This distribution has remained stable since 2020. The chapter tests three core NCERT topics: magnetic field due to a current (including straight conductor, circular loop and solenoid), electromagnetic induction (Faraday's experiments and induced current direction), and practical devices (electric motor and AC generator). Understanding the difference between motor effect and generator effect is crucial, as CBSE loves to ask comparative questions. Diagrams are compulsory in 3-mark and 5-mark answers and can fetch 1.5-2 marks independently if drawn with proper labelling, arrows showing current or field direction, and neat presentation.

Expected weightage: 5-7 marks out of 80 in the theory paper
Question format: 2 MCQs (1 mark each), 1-2 short answers (2-3 marks), 1 long answer or case study (4-5 marks)
Diagram questions appear in at least 40 per cent of papers since 2022
Numerical problems on magnetic field strength or induced EMF are common in 2-mark slots
Comparative questions (motor vs generator, AC vs DC) frequently appear as 3-mark questions

1-Mark Questions: MCQs and Very Short Answer (VSA)

The CBSE board paper includes two MCQs from this chapter, each worth 1 mark. These test definitions, rules and quick identification of devices or phenomena. VSA questions demand one-sentence or one-word answers. Preparation tip: revise all bold-print terms from NCERT pages 224-240, particularly magnetic field lines properties, right-hand thumb rule statement, Fleming's rules, and the principle of electromagnetic induction. MCQs often present diagrams of magnetic field patterns or device cross-sections and ask you to identify the setup. Pay attention to direction arrows in diagrams. Below are six representative 1-mark questions with answers. Practice these to secure full marks in the objective section, as even one wrong MCQ costs you a full mark with no partial credit in the current CBSE scheme.

2-Mark Questions with Model Answers

Two-mark questions test slightly deeper understanding and often require a labelled diagram or a two-step explanation. Common formats include: state and explain a rule, draw and label a magnetic field pattern, write two differences, or solve a simple numerical problem. CBSE marking schemes award 1 mark for correct concept and 1 mark for clarity, diagram or numerical working. Always write answers in point form or short sentences to save time. Mention exact NCERT terminology such as 'magnetic field due to a current' and 'electromagnetic induction' rather than loose paraphrasing. Numerical problems typically involve calculating the magnetic field at the centre of a circular loop or near a solenoid, given current and coil parameters. Remember to write the formula, substitute values with units, and box the final answer. Below are four carefully selected 2-mark questions mirroring the 2023-2025 board exam style, each with a concise model answer.

3-Mark Questions with Model Answers

Three-mark questions demand a clear explanation, a well-labelled diagram, or a three-point answer. Fleming's Left Hand Rule and Fleming's Right Hand Rule questions almost always carry 3 marks and require both statement and diagram. Similarly, explaining the working of an electric motor or the principle of electromagnetic induction fetches 3 marks when accompanied by a neat diagram. CBSE awards 1 mark for the statement/principle, 1.5 marks for the diagram with labels, and 0.5 mark for clarity. Write the answer in three distinct points or sub-headings to make marking easier for examiners. Avoid long paragraphs. Use bullet points wherever possible. Remember that Fleming's Left Hand Rule applies to motors (force on current-carrying conductor in magnetic field) while Fleming's Right Hand Rule applies to generators (induced current direction). Mixing these rules is the most common error. Below are four representative 3-mark questions with structured model answers.

5-Mark Questions and Case-Based Questions

Five-mark questions are the backbone of scoring high in this chapter. They test comprehensive understanding of devices like electric motor and AC generator. A typical 5-mark question asks you to explain the working principle, construction, and function of parts with a neat labelled diagram. CBSE marking schemes allocate roughly 2 marks for the diagram, 2 marks for explanation of working, and 1 mark for principle or advantages. Since 2021, case-based questions (4-5 marks) have become common. These present a real-life scenario—such as a hydroelectric power plant, a table fan, or an MRI machine—and ask 3-4 sub-questions testing application of concepts. Read the case passage carefully and underline key data before attempting. Use NCERT terminology: 'magnetic field due to a current,' 'electromagnetic induction,' 'split ring commutator,' 'slip rings,' 'armature coil.' Write in structured points with sub-headings like Principle, Construction, Working, and Advantages. Below are three long-answer questions and one case study with model answers.

Numerical Problems from Magnetic Effects of Electric Current

Numerical problems are less frequent in this chapter compared to Electricity (Chapter 12) but do appear, especially in 2-mark slots. Common topics include calculating the magnetic field at the centre of a circular coil, estimating the number of turns in a solenoid given field strength and current, or determining the direction and magnitude of force on a current-carrying conductor in a magnetic field using F equals BIL. Always write the formula first, substitute values with correct SI units (Ampere for current, Tesla for magnetic field, metre for length), perform the calculation step-by-step, and underline or box the final answer with unit. In exams, even if your final answer is wrong, you earn partial marks for correct formula and substitution. Remember that magnetic field B inside a long solenoid is given by B equals mu-nought times n times I, where n is number of turns per unit length and I is current. For a circular loop, B at centre equals (mu-nought times I) divided by (2R). Practice these formulas from NCERT examples on pages 229-231.

Formula for magnetic field at centre of circular coil: B = (μ₀I)/(2R), where μ₀ = 4π × 10⁻⁷ T m A⁻¹
Formula for solenoid: B = μ₀nI, where n = N/L (turns per metre)
Force on conductor: F = BIL sin θ (maximum when θ = 90°, i.e. F = BIL)
Always write unit in final answer: Tesla (T) for magnetic field, Newton (N) for force
Show all substitution steps to earn partial marks even if calculation is incorrect

How CBSE Frames Questions from This Chapter

CBSE question-setters follow a predictable pattern when framing questions from Magnetic Effects of Electric Current. Almost every year since 2018, one 3-mark question asks you to state Fleming's Left Hand Rule or Right Hand Rule and draw a labelled diagram. One 2-mark question tests the difference between AC and DC, or motor and generator, in tabular form. One MCQ (1 mark) presents a diagram of magnetic field lines and asks you to identify the pattern or device. Long-answer questions (5 marks) focus on explaining the working of electric motor or AC generator with diagram; these appear in roughly 60 per cent of papers. Case-based questions introduced post-2020 often describe real-world applications—electric bell, loudspeaker, MRI scanner, or hydroelectric plant—and ask 3-4 sub-questions totaling 4-5 marks. Examiners love to test cause-and-effect understanding: 'Why does the coil rotate?' 'What happens if split rings are removed?' 'How does increasing current affect magnetic field strength?' Always support your answer with the underlying NCERT principle. Diagrams must be drawn in pencil, labelled in ink, with clear arrowheads for directions. Missing direction arrows cost you 0.5-1 mark per diagram. Practice past years' papers from 2018-2024 to internalize these patterns.

Fleming's rules + diagram: appears in 70 per cent of papers as 3-mark question
Motor or generator working: one 5-mark descriptive question almost guaranteed
Difference-based questions: AC vs DC, motor vs generator, solenoid vs bar magnet (2 marks)
Application-based MCQs: identify device from diagram or match principle to application
Numerical problems: 10-15 per cent of papers include a 2-mark calculation on magnetic field or force
Case studies: 30-40 per cent of recent papers feature a 4-5 mark case linking chapter concepts to real life

Common Mistakes Students Make and How to Avoid Them

Students lose easy marks in this chapter due to avoidable errors. The single biggest mistake is confusing Fleming's Left Hand Rule (used for motors, force on conductor) with Fleming's Right Hand Rule (used for generators, direction of induced current). A simple mnemonic: Left for 'Locomotion' (motor), Right for 'Renaissance' (generation of current). Second common error: forgetting to draw direction arrows on diagrams. A magnetic field line without arrowhead, or a current symbol without direction, earns zero marks for that part of the diagram. Always use arrowheads and label them clearly as B (magnetic field), I (current), F (force), or v (velocity). Third mistake: writing long paragraphs instead of point-wise answers. CBSE markers prefer structured answers with clear sub-headings. For a 5-mark motor question, use four sub-headings: Principle, Construction, Working, Advantages. Fourth error: incorrect or missing units in numerical answers. Magnetic field must be in Tesla (T) or milliTesla (mT), force in Newton (N), current in Ampere (A). Fifth mistake: misunderstanding the function of split rings vs slip rings. Split rings reverse current direction (motor), slip rings maintain continuous contact without reversing current (AC generator). Write one sentence on function in every motor or generator answer to secure that 0.5 mark. Practice drawing diagrams daily—use NCERT figures on pages 233, 236, 238 as templates. Time yourself: a good diagram should take 2-3 minutes maximum in the exam.

Mixing up Fleming's Left Hand Rule and Right Hand Rule—revise which applies to motor vs generator
Omitting direction arrows or labels on diagrams—costs 0.5-1 mark per missing arrow
Writing prose paragraphs instead of point-wise or tabular answers in 2-mark and 3-mark questions
Forgetting units in numerical answers—always write Tesla, Newton, Ampere with final answer
Confusing split rings (commutator in motor) with slip rings (in AC generator)—state function clearly
Not practising diagram drawing—invest 10 minutes daily sketching motor, generator, field patterns from NCERT

Tips for Scoring Full Marks in Board Exam

Scoring full marks in Magnetic Effects of Electric Current requires clarity, accuracy and smart time management. First, memorize all definitions and rules verbatim from NCERT: 'Electromagnetic induction is the phenomenon of producing an induced current in a coil due to change in magnetic flux linked with it.' Use these exact words in your answers. Second, practice diagrams until you can draw them blindfolded. Label every part: coil, magnet poles (N-S), brushes, split rings or slip rings, battery terminals, direction of current (I), magnetic field (B), and force or motion (F). Use a sharp pencil for diagrams and ink pen for labels. Third, for 5-mark questions, divide your answer into Principle (1 mark), Construction/Diagram (2 marks), Working (1.5 marks), Advantages or Conclusion (0.5 mark). Write sub-headings in bold or underline them. Fourth, revise the difference tables: AC vs DC, motor vs generator, solenoid vs bar magnet, Fleming's Left vs Right. CBSE loves 2-mark tabular questions. Fifth, solve at least 10 previous years' question papers (2015-2024) available on cbse.nic.in. Note the repeated question types. Sixth, for case-based questions, underline or highlight numerical data and key terms in the passage before attempting sub-questions. Finally, allocate time wisely in the exam: 1-mark questions should take 30 seconds, 2-mark questions 2-3 minutes, 3-mark questions 4-5 minutes, 5-mark questions 8-10 minutes. If stuck, move on and return later. Every mark counts toward your final percentage.

Learn NCERT definitions word-by-word; examiners reward precise language
Draw diagrams in pencil, label in ink, include all direction arrows and part names
Structure 5-mark answers with clear sub-headings: Principle, Construction, Working, Advantages
Prepare difference tables in advance for quick recall in 2-mark questions
Solve 10 past years' CBSE papers to internalize question patterns and marking schemes
In case-based questions, read passage twice and underline key data before answering
Time management: 30s per MCQ, 2-3 min per 2-mark, 4-5 min per 3-mark, 8-10 min per 5-mark question

How CBSETUTOR.ai Helps You Master This Chapter

Parents in cities like Delhi, Bangalore, Mumbai and Pune often worry whether their child truly understands concepts like electromagnetic induction or can draw motor diagrams correctly under exam pressure. Coaching centres charge ₹15,000-25,000 for a full-year Science course, and many students still struggle with application-based questions. CBSETUTOR.ai offers a smarter, more affordable solution: a 24×7 AI tutor available on your phone for a flat ₹999 per month—one price for every class from 6 to 12, no hidden fees. Your child can snap a photo of any question from Chapter 12 Magnetic Effects of Electric Current—whether it is a tricky numerical, a diagram-based question, or a case study—and get an instant step-by-step solution aligned with CBSE marking schemes. The AI tutor explains why Fleming's Left Hand Rule applies here, how to label the diagram, which formula to use, and common examiner traps to avoid. Unlike recorded video lectures, CBSETUTOR.ai is interactive: your child can ask follow-up questions, request alternate explanations, or practice similar questions until the concept clicks. The platform also tracks progress, highlights weak areas, and suggests targeted practice questions. Many parents report that their children gain confidence within the first week of use, especially in diagram-heavy chapters like this one. Start with the 3-day free trial—no credit card required—and see your child solve Magnetic Effects questions independently and accurately. Visit CBSETUTOR.ai today.

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Frequently asked questions

How many marks does Chapter 12 Magnetic Effects of Electric Current carry in CBSE Class 10 board exam?+

This chapter typically carries 5-7 marks in the 80-mark theory paper. Expect 2 MCQs (1 mark each), 1-2 short-answer questions (2-3 marks each), and one long-answer or case-based question (4-5 marks). The exact distribution varies slightly each year, but total weightage remains 5-7 marks.

What is the difference between Fleming's Left Hand Rule and Fleming's Right Hand Rule?+

Fleming's Left Hand Rule is used to find the direction of force (or motion) on a current-carrying conductor in a magnetic field; it applies to electric motors. Fleming's Right Hand Rule is used to find the direction of induced current when a conductor moves in a magnetic field; it applies to electric generators. Remember: Left for motor (force/motion), Right for generator (induced current).

Which diagrams are most important to practice for this chapter?+

You must practice four diagrams: (1) Magnetic field lines around a straight current-carrying conductor (concentric circles). (2) Magnetic field pattern of a solenoid. (3) Labelled diagram of an electric motor showing coil, split rings, brushes, magnet poles, and direction arrows. (4) Labelled diagram of an AC generator showing slip rings, brushes, rotating coil, and magnet. Draw these daily using NCERT figures as reference.

Do numerical problems appear from this chapter in the board exam?+

Yes, but less frequently than from Electricity chapter. Expect one 2-mark numerical on calculating magnetic field at the centre of a circular coil or inside a solenoid, or finding force on a current-carrying conductor using F equals BIL. Revise formulas: B equals (mu-nought I)/(2R) for circular loop, B equals mu-nought nI for solenoid. Practice NCERT examples on pages 229-231.

What is electromagnetic induction and why is it important?+

Electromagnetic induction is the phenomenon of producing an induced current in a coil when the magnetic flux linked with it changes. It is the working principle of AC generators, transformers, and many modern electrical devices. CBSE frequently asks 3-5 mark questions on this concept, including stating Faraday's experiments, factors affecting induced current magnitude, and applications. Revise NCERT pages 234-236 thoroughly.

What is the function of split rings in an electric motor?+

Split rings act as a commutator in an electric motor. They reverse the direction of current flowing through the armature coil every half rotation. This reversal ensures that the forces on the two sides of the coil continue to act in directions that rotate the coil in the same sense, producing continuous rotation. Without split rings, the coil would oscillate, not rotate continuously.

How should I write a 5-mark answer on the working of AC generator?+

Structure your answer in four parts: (1) Principle: State that it works on electromagnetic induction—when coil rotates in magnetic field, flux changes, inducing current. (2) Construction: Draw labelled diagram showing rectangular coil, magnet poles N-S, slip rings, brushes. (3) Working: Explain how rotation changes flux, inducing alternating current; direction reverses every half turn as per Fleming's Right Hand Rule. (4) Advantages: Simple, widely used in power stations. Allocate roughly 2 marks for diagram, 2 for working, 1 for principle and advantages.

What are the common mistakes students make in this chapter?+

Top mistakes: (1) Confusing Fleming's Left and Right rules. (2) Missing direction arrows or labels in diagrams. (3) Writing paragraph answers instead of point-wise explanations. (4) Forgetting units in numerical answers (Tesla, Newton). (5) Confusing split rings (motor) with slip rings (generator). (6) Not practising diagrams, leading to incomplete or incorrect drawings in the exam. Avoid these by daily revision and diagram practice.

How much time should I spend on a 5-mark question from this chapter in the exam?+

Allocate 8-10 minutes for a 5-mark question. Spend 2 minutes drawing and labelling the diagram neatly in pencil. Use the remaining 6-8 minutes to write the explanation in point form covering principle, construction, working, and advantages. If you run short on time, ensure the diagram is complete and labelled, as it alone fetches 1.5-2 marks.

Are case-based questions asked from Magnetic Effects of Electric Current?+

Yes, since 2021 CBSE includes case-based questions worth 4-5 marks. A typical case describes a real-life application—hydroelectric plant, electric bell, MRI machine—and asks 3-4 sub-questions testing your understanding of motor, generator, or electromagnetic induction principles. Read the passage carefully, underline key data, and answer each sub-question with specific reference to NCERT concepts.

Which NCERT exercises and examples should I solve for this chapter?+

Solve all in-text questions on pages 228, 231, 233, 237, and 239, and all end-of-chapter exercises (Q1-Q13) on pages 240-241. Pay special attention to Examples 13.1, 13.2, and 13.3 that demonstrate how to apply right-hand thumb rule, calculate magnetic field, and explain device working. Practice drawing and labelling all figures from pages 224-238 to master diagrams.

How can CBSETUTOR.ai help me prepare for this chapter?+

CBSETUTOR.ai provides a 24×7 AI tutor accessible on your phone for ₹999/month flat fee across all classes and subjects. Snap a photo of any Chapter 12 question—MCQ, diagram, numerical, or case study—and get instant step-by-step solutions aligned with CBSE marking schemes. The AI explains concepts interactively, helps you practice diagrams with feedback, and tracks your progress to highlight weak areas. Start with a 3-day free trial at CBSETUTOR.ai.

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