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IGCSE · 4 · multiple choice

Electricity and magnetism · Question 5

Electricity and magnetism · Original GioPhysics question with a detailed, mark-by-mark answer guide.

Demand
recall
Marks
1
Topics
1
Answer
Complete
A current-carrying wire crossing the field between two magnet polesNmagnetSmagnetmagnetic fieldIwire carrying a current
Fig. 5.1Two magnets face each other across a gap, the left one presenting its north pole and the right one its south pole, with the flat pole faces vertical and parallel. Four horizontal arrows drawn across the gap from the north pole to the south pole represent the magnetic field. A straight wire runs vertically down the page through the middle of the gap, so that it crosses the field lines at right angles, and a short arrow on the wire labelled I shows the current flowing up the page.
multiple choice1 mark

A straight wire carrying a current is placed at right angles to a magnetic field. In which direction does the force on the wire act?

  1. A

    along the wire, in the direction of the current

  2. B

    along the magnetic field lines

  3. C

    at right angles to both the current and the field

  4. D

    there is no force unless the wire moves

Ready to self-mark?Reveal the detailed answer guide
Answer overviewCorrect answer: C — at right angles to both the current and the field
01

Answer and reasoning

1 mark
How to approach it

Predict from the governing principle before looking for a matching option. Then reject alternatives by checking direction, units, limiting behaviour or the physical meaning of each statement.

  1. 1

    The correct choice is C: at right angles to both the current and the field

  2. 2

    D confuses the motor effect with electromagnetic induction — a current-carrying wire in a field experiences a force whether or not it is moving.

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