Lesson 7.4.1

7.4.1 Magnetic flux density and forces on charges and currents Quiz: Pearson Edexcel Physics, Unit 7

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson 7.4.1, Magnetic flux density and forces on charges and currents: 20 multiple choice questions for the Pearson Edexcel Physics (9PH0), Unit 7: Electric and Magnetic Fields, written with Revision Ninja.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. How is magnetic flux density B defined for a conductor perpendicular to the field?

    • The energy stored per unit volume in the magnetic field, B = W / V
    • The force per unit current per unit length of the conductor, B = F / (Il)
    • The force per unit charge on a stationary particle in the field, B = F / q
    • The magnetic flux through unit area of any surface, B = phi A

  2. What is the SI unit of magnetic flux density?

    • The henry, equivalent to V s A^-1
    • The weber, equivalent to T m^2
    • The tesla, equivalent to N A^-1 m^-1
    • The newton, equivalent to kg m s^-2

  3. For a current-carrying wire in a magnetic field, what does theta represent in F = BIl sin(theta)?

    • The angle through which the wire has been rotated from its original position
    • The angle between the wire and the vertical direction of gravity
    • The angle between the direction of the current and the direction of the magnetic field
    • The angle between the magnetic field and the plane containing the wire

  4. In Fleming's left-hand rule, what does the second finger represent?

    • The direction of the resultant force
    • The direction of the magnetic field
    • The direction of the electron motion in the wire
    • The direction of the conventional current

  5. Which equation gives the magnetic force on a charged particle of charge q and speed v moving in a magnetic field B?

    • F = B q / v
    • F = B q v / sin(theta)
    • F = B q^2 v
    • F = B q v sin(theta)

  6. Magnetic flux is defined as the product of which two quantities for a flat surface perpendicular to the field?

    • Magnetic flux density and area
    • Magnetic flux density and current
    • Magnetic flux density and force
    • Magnetic flux density and time

  7. What is flux linkage for a coil of N turns, each linked by magnetic flux phi?

    • N phi
    • N squared phi
    • phi / N
    • N + phi

  8. A wire of length 0.25 m carries a current of 4.0 A perpendicular to a uniform magnetic field of flux density 0.30 T. What is the force on the wire?

    • 0.075 N
    • 3.3 N
    • 1.2 N
    • 0.30 N

  9. A wire of length 0.40 m carries 5.0 A at 30 degrees to a uniform field of flux density 0.20 T. What is the force on the wire?

    • 0.17 N
    • 0.20 N
    • 0.35 N
    • 0.40 N

  10. An electron travels at 2.0 x 10^6 m s^-1 perpendicular to a magnetic field of flux density 0.010 T. What is the magnetic force on it?

    • 1.3 x 10^-15 N
    • 3.2 x 10^-15 N
    • 3.2 x 10^-13 N
    • 3.2 x 10^-17 N

  11. A proton moves parallel to the lines of a uniform magnetic field. What is the magnetic force on it?

    • Equal to qE
    • Equal to Bqv
    • Equal to Bq
    • Zero

  12. A flat surface of area 0.020 m^2 lies perpendicular to a uniform magnetic field of flux density 0.50 T. What is the magnetic flux through it?

    • 25 Wb
    • 0.010 Wb
    • 0.0040 Wb
    • 0.040 Wb

  13. A coil of 200 turns has the same magnetic flux of 0.010 Wb through each turn. What is its flux linkage?

    • 20 Wb
    • 0.050 Wb
    • 2.0 Wb
    • 0.010 Wb

  14. A wire carries current to the right in a magnetic field directed into the page. In which direction is the force on the wire?

    • Upwards, in the plane of the page
    • To the left, in the plane of the page
    • Out of the page
    • Downwards, in the plane of the page

  15. A wire of length 0.50 m carries 3.0 A at 60 degrees to a uniform field of flux density 0.40 T. What is the force on the wire?

    • 1.2 N
    • 0.26 N
    • 0.52 N
    • 0.60 N

  16. A flat coil of 50 turns and area 0.020 m^2 lies perpendicular to a uniform field of flux density 0.10 T. What is the flux linkage?

    • 0.010 Wb
    • 1.0 Wb
    • 0.40 Wb
    • 0.10 Wb

  17. An electron enters a magnetic field of flux density 0.20 T at 30 degrees to the field with speed 4.0 x 10^6 m s^-1. What is the magnetic force on it?

    • 6.4 x 10^-14 N
    • 3.2 x 10^-14 N
    • 1.3 x 10^-19 N
    • 1.3 x 10^-13 N

  18. Why does a magnetic field do no work on a charged particle moving in it?

    • The magnetic force is zero whenever the particle is moving at a constant speed
    • The magnetic force is always perpendicular to the velocity, so it changes the direction of motion but not the kinetic energy
    • The magnetic force is always parallel to the velocity, so it only changes the speed of the particle
    • The magnetic field stores all the energy of the moving particle as magnetic potential energy

  19. A student says a magnetic field exerts a force on a stationary charge. Which response is correct?

    • The student is wrong: the magnetic force is Bqv sin(theta), which is zero when the charge is not moving
    • The student is right, but only if the stationary charge is positive
    • The student is wrong because magnetic fields exert forces only on neutral objects
    • The student is right: any charge in a magnetic field feels a force whether it is moving or not

  20. A student uses F = BIl without the sin(theta) term for a wire at an angle to the field. What error results?

    • The force is overestimated, because only the component of the field perpendicular to the wire produces a force
    • The force is unchanged, because the angle between the wire and the field does not matter
    • The force is reversed in direction, because the wire is at an angle to the field
    • The force is underestimated, because the sin(theta) term always adds to the field strength

All Pearson Edexcel Physics quizzes