Practise 39 real Federal Board questions on Electromagnetism from 2023 to 2026. See the answer and explanation as soon as you answer.
Electromagnetism is one of the 14 main chapters in our Federal Board FSC Physics question bank (11th and 12th class), and about 8% of its real questions come from it. Tayyari Karo has 39 real questions on this chapter from 2023 to 2026; 11 are multiple choice and marked instantly, and the rest are short and long questions with a model answer. By difficulty: 29 medium, 9 easy, 1 hard.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
These are real past-paper questions. Think of your answer first, then open the explanation.
What is the motion of an electron moving at an angle of 45° to a uniform magnetic field?
Answer: D. Helical motion
With velocity components both parallel and perpendicular to B, the electron moves in a helical (spiral) path along the field direction.
Two closely placed parallel wires carrying current in opposite directions; the wires will:
Answer: A. Repel each other
Parallel conductors carrying currents in opposite directions repel each other (currents in the same direction attract).
Which is an application of Mutual Induction?
Answer: B. Transformer
A transformer works by mutual induction between its primary and secondary coils.
Magnetic flux Φ through a surface area A is:
Answer: B. B·A
Magnetic flux is the dot product of the field and the area vector, Φ = B·A.
The temperature at which a ferromagnetic material becomes paramagnetic is called:
Answer: D. Curie temperature
Above the Curie temperature, thermal agitation destroys the magnetic domain alignment and the material becomes paramagnetic.
The S.I. unit of magnetic flux is:
Answer: B. Weber
Magnetic flux is measured in Weber (Wb); Tesla is the unit of magnetic flux density (field), not flux.
Derive an expression for the magnetic force experienced by a moving charge in a uniform magnetic field. Also discuss the direction of that force.
When a charge q moves with velocity v̄ through a uniform magnetic field B̄, it experiences a magnetic (Lorentz) force. Experimentally, this force is found to be:
• Proportional to the charge q
• Proportional to the speed v
• Proportional to sinθ, where θ is the angle between v̄ and B̄
• Always perpendicular to both v̄ and B̄
Combining these into a single vector expression:
F̄ = qv̄ × B̄, with magnitude F = qvB sinθ
Direction: Given by the right-hand rule: point the fingers of the right hand along v̄, curl them towards B̄; the thumb points in the direction of v̄×B̄ (the direction of force on a positive charge — for a negative charge, the force is reversed). …
The full model answer is in the app.
Briefly explain the construction and working of a transformer.
Construction: A transformer consists of a laminated soft-iron core with two separate coils of insulated wire wound on it — the primary coil (Np turns), connected to the AC input source, and the secondary coil (Ns turns), connected to the output/load.
Working: An alternating current in the primary coil produces a changing magnetic flux in the iron core, which links the secondary coil (the core efficiently guides nearly all the flux to the secondary). By Faraday's law, this changing flux induces an alternating emf in the secondary coil. The ratio of secondary to primary voltage equals the ratio of their turns: Vs/Vp = Ns/Np. …
The full model answer is in the app.
| Session | Questions |
|---|---|
| 2026 Annual | 3 |
| 2025 1st Annual | 12 |
| 2025 2nd Annual | 12 |
| 2024 Annual | 7 |
| 2023 Annual | 5 |
39 real Federal Board (FBISE) Physics questions on Electromagnetism from 2023 to 2026, for 11th and 12th class. Each one shows the session it came from.
No. We could not find an official FBISE marking scheme for these papers, so the answers and explanations are written by Tayyari Karo for practice. Check anything important with your teacher or textbook.
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