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Leaving Cert Physics & Chemistry: Magnetic fields & the motor effect

How often Magnetic fields & the motor effect comes up on the Physics & Chemistry papers, every year it was asked, and questions to try.

HL Asked on 8 of the last 9 Higher Level papers, most recently in 2025. most years

OL Asked on 7 of the last 9 Ordinary Level papers, most recently in 2024. most years

Magnetic fields & the motor effect, Higher Level(8 marks)

Quick ones on Magnetic fields & the motor effect.

(a)In Fleming's left-hand rule, the thumb shows the direction of…
  1. The current
  2. The force (motion)
  3. The magnetic field
(b)Which change reverses the force on a current-carrying wire in a magnetic field?
  1. Using a longer wire
  2. Doubling the current
  3. Reversing the current
(c)How is a moving-coil galvanometer converted to a voltmeter?
  1. A large resistance in series
  2. A capacitor in parallel
  3. A small resistance in parallel
Show the answers

(a) The force (motion)

(b) Reversing the current

(c) A large resistance in series

Your turn: Higher Level questions on Magnetic fields & the motor effect.

Higher Level

Asked on 8 of the last 9 Higher Level papers, most recently in 2025. most years

Every paper, year by year

YearWhere it came up
2025Q1(n)
2024Q1(p), Q6(c)
2023Q1(m)
2022Q1(o), Q1(p)
2021Q5
2019Not asked
2018Q1(l)
2017Q1(l), Q5
2016Q1(l)

Links open the State Examinations Commission’s paper for that year.

More Magnetic fields & the motor effect questions

Magnetic fields & the motor effect, 3 marks

The force on a current-carrying wire in a magnetic field is greatest when the wire is…

  1. Parallel to the field
  2. At 45° to the field
  3. At right angles to the field
Show the answer

At right angles to the field

The force is largest when the current crosses the field lines at 90°. A wire lying along the field lines feels no force at all.

Magnetic fields & the motor effect, 2 marks

Outside a bar magnet, the magnetic field lines run from…

  1. The centre of the magnet outwards
  2. The north pole to the south pole
  3. The south pole to the north pole
Show the answer

The north pole to the south pole

Field lines show the direction a free north pole would move: away from the magnet's north pole and round to its south pole.

Ordinary Level

Asked on 7 of the last 9 Ordinary Level papers, most recently in 2024. most years

Every paper, year by year

YearWhere it came up
2025Not asked
2024Q1(n), Q1(p)
2023Q1(p)
2022Q1(o)
2021Q1(k)
2019Not asked
2018Q1(i), Q1(j)
2017Q1(l)
2016Q1(l)

Links open the State Examinations Commission’s paper for that year.

More Magnetic fields & the motor effect questions

Magnetic fields & the motor effect, 2 marks

A current-carrying wire is placed across a magnetic field. It?

  1. Loses its current
  2. Becomes a permanent magnet
  3. Experiences a force
Show the answer

Experiences a force

This is the motor effect. The field of the current and the magnet's field interact, pushing the wire. It is the basis of the electric motor.

Magnetic fields & the motor effect, 2 marks

Fleming's left-hand rule gives the direction of?

  1. The magnetic field around a bar magnet
  2. The force on a current-carrying conductor
  3. The induced current in a dynamo's coil
Show the answer

The force on a current-carrying conductor

First finger = field, second finger = current, thumb = motion (force). Hold them at right angles to each other.

Magnetic fields & the motor effect, 3 marks

The current in a wire in a magnetic field is reversed. The force on the wire?

  1. Reverses direction
  2. Doubles
  3. Becomes zero
Show the answer

Reverses direction

Force direction depends on both the current direction and the field direction. Reverse either one and the wire is pushed the other way.

Other Physics & Chemistry topics

All of Leaving Cert Physics & Chemistry