Force on a Current-Carrying Conductor; Induction and Transformers: JAMB Physics Questions, Answers & Notes

What Force on a Current-Carrying Conductor; Induction and Transformers covers in the JAMB Physics syllabus

A current-carrying conductor in a magnetic field feels a force (the motor effect); its direction is given by Fleming's left-hand rule (thuMb–First–seCond = Motion–Field–Current), and the force is greatest when current is perpendicular to the field. This effect drives the electric motor. Conversely, a changing magnetic flux induces an e.m.f. (electromagnetic induction): Faraday's law relates the e.m.f. to the rate of change of flux, and Lenz's law says the induced current opposes the change. Generators use this. A transformer works by mutual induction with a.c.: Vs/Vp = Ns/Np. Power is sent at high voltage, low current to cut I²R losses.

For Force on a Current-Carrying Conductor; Induction and Transformers, JAMB expects you to be able to:

• Explain the motor effect and Fleming's left-hand rule
• Explain electromagnetic induction, Faraday's and Lenz's laws and the generator
• Describe the transformer and its use in power transmission

Key facts & revision notes: Force on a Current-Carrying Conductor; Induction and Transformers

These are the recurring points our Force on a Current-Carrying Conductor; Induction and Transformers questions test — revise them until each feels automatic, then practise the questions above to lock them in.

• A current-carrying conductor in a magnetic field experiences a force (the motor effect).
• Fleming's left-hand rule gives the direction of the force (motor effect).
• In Fleming's left-hand rule: thumb = force/motion, first finger = field, second finger = current.
• The electric motor uses the force on current-carrying coils in a magnetic field to produce rotation.
• A generator/dynamo uses electromagnetic induction to produce current from a changing magnetic field.
• Electromagnetic induction is the production of an e.m.f.
• by a changing magnetic field.
• Faraday's law: the induced e.m.f.
• is proportional to the rate of change of magnetic flux.
• Lenz's law: the induced current flows so as to oppose the change that produces it (conservation of energy).
• Fleming's right-hand rule gives the direction of the induced current (generator effect).
• A transformer transfers energy between coils by mutual induction of a changing magnetic flux.
• A step-up transformer increases voltage (more turns on the secondary coil).
• In an ideal transformer, the voltage ratio equals the turns ratio: Vs/Vp = Ns/Np.
• Vs = Vp × (Ns/Np) = 100 × (800/200) = 100 × 4 = 400 V.
• Transformers need a changing magnetic flux, so they work with a.c., not steady d.c.
• The force grows with larger current, stronger field and greater conductor length in the field.
• The force is zero when the current is parallel to the field, and maximum when perpendicular to it.
• Eddy currents induced in the core cause heating; they are reduced by laminating the core.
• A step-down transformer lowers the voltage; for an ideal transformer the current rises correspondingly.
• Transformers step voltage up for transmission and down for use, efficiently and with a.c.
• High voltage means low current, which minimises the I²R heat losses in transmission lines.
• Maximum force occurs when the wire is perpendicular to the field.
• First finger = field, seCond finger = current, thuMb = motion/force.

Worked examples

Three Force on a Current-Carrying Conductor; Induction and Transformers questions with the answer and a short explanation, so you can see how the topic is set before you practise the full set.

How Force on a Current-Carrying Conductor; Induction and Transformers is tested in JAMB Physics

Our Force on a Current-Carrying Conductor; Induction and Transformers bank holds 40 questions (1 easy, 24 medium, 15 hard). JAMB Physics typically returns to Force on a Current-Carrying Conductor; Induction and Transformers year after year, so steady practice on this topic is high-value revision. Questions are multiple-choice with four options, and at UTME pace you get roughly 40 seconds each — which is why timed practice matters.

How to answer Force on a Current-Carrying Conductor; Induction and Transformers questions

Work the stem first and predict the answer before you look at the options; then eliminate the ones that contradict the key facts above. Watch for “which is not…”, “all of the above” and “except” style stems, which are where rushed candidates lose easy marks on Force on a Current-Carrying Conductor; Induction and Transformers. If a calculation or a precise definition is involved, work it from first principles rather than guessing from a half-remembered rule. When two options look right, re-read the stem for the qualifier that separates them — JAMB rarely repeats an option by accident. If you are still unsure, eliminate the two weakest choices to lift your odds, flag the question, and move on; never burn a full minute on one Physics item when the exam gives you about forty seconds each. Then come back to flagged questions with whatever time remains. The single most reliable way to get faster at Force on a Current-Carrying Conductor; Induction and Transformers is repeated timed practice, so use the button above until the recurring patterns feel automatic.

Common mistakes to avoid in Force on a Current-Carrying Conductor; Induction and Transformers

The errors that cost marks on Force on a Current-Carrying Conductor; Induction and Transformers are usually careless rather than conceptual: misreading a negative stem, confusing two similar terms, or rushing a definition you actually know. Candidates also over-rely on “expo” and last-minute cramming instead of understanding the topic — which fails the moment JAMB rephrases a familiar idea. Treat every option as a claim to be checked against the facts above, keep your working tidy for any calculation, and don’t change a considered answer on a hunch. Above all, revise Force on a Current-Carrying Conductor; Induction and Transformers actively by answering questions, not just by re-reading notes — recall under time is what the exam rewards.

Frequently asked questions

Is Force on a Current-Carrying Conductor; Induction and Transformers part of the JAMB Physics syllabus?

Yes. Force on a Current-Carrying Conductor; Induction and Transformers is a recognised topic in the JAMB Physics syllabus, covering explain the motor effect and Fleming's left-hand rule. You should be able to recall its key facts and apply them to multiple-choice questions.

How many Force on a Current-Carrying Conductor; Induction and Transformers questions can I practise on Belmadeng?

There are 40 original, JAMB-standard Force on a Current-Carrying Conductor; Induction and Transformers questions in our free bank, each with the correct answer and a worked explanation. You can practise them untimed or as a timed test.

What are the most important points to know about Force on a Current-Carrying Conductor; Induction and Transformers?

A current-carrying conductor in a magnetic field feels a force (the motor effect); its direction is given by Fleming's left-hand rule (thuMb–First–seCond = Motion–Field–Current), and the force is greatest when current is perpendicular to the field. This effect drives the electric motor. Conversely, …

How do I answer Force on a Current-Carrying Conductor; Induction and Transformers questions quickly in JAMB?

Read the stem carefully, eliminate clearly wrong options, and match the remaining choices to the key facts for Force on a Current-Carrying Conductor; Induction and Transformers. Practising timed Force on a Current-Carrying Conductor; Induction and Transformers questions builds the speed you need for UTME's pace of about 40 seconds per question.

Are these JAMB Physics Force on a Current-Carrying Conductor; Induction and Transformers questions past questions or original?

They are original questions written to JAMB (UTME) standard and mapped to the official syllabus — not reproduced past papers. This keeps them legal to use freely while closely mirroring how the real exam tests the topic.

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Right here — tap “Start Force on a Current-Carrying Conductor; Induction and Transformers practice” on this page to begin instantly. Belmadeng's CBT practice is completely free and needs no sign-up, download or subscription.

About these questions: original, JAMB-standard items written from the official UTME Physics syllabus (last reviewed 2026-09-18). Belmadeng is an independent study platform and is not affiliated with JAMB. Spotted an error? Use the report link.