Lesson 6.3.2

6.3.2 Motion of charged particles Quiz: OCR Physics, Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 6.3.2, Motion of charged particles: 20 multiple choice questions for the OCR Physics (H156), Unit 5: Particles and medical physics, written with Revision Ninja.

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The 20 questions

  1. What is the SI unit used to measure magnetic flux density?

    • Weber
    • Henry
    • Gauss
    • Tesla

  2. What is the SI unit used for measuring magnetic flux?

    • Volt
    • Tesla
    • Weber
    • Farad

  3. Which formula gives the magnetic force on a charge Q moving at speed v?

    • F = BIL
    • F = Bv/Q
    • F = EQ
    • F = BQv

  4. What path does a charged particle follow when moving perpendicular to a uniform B-field?

    • Parabolic path
    • Straight line
    • Circular orbit
    • Helical spiral

  5. Which device uses perpendicular electric and magnetic fields to select charged particles by speed?

    • Synchrotron
    • Mass spectrometer
    • Cyclotron
    • Velocity selector

  6. What equation gives the selected particle velocity v in a velocity selector?

    • v = E + B
    • v = E / B
    • v = B / E
    • v = E B

  7. Which law states that induced e.m.f. equals the rate of change of magnetic flux linkage?

    • Lenz's law
    • Ampere's law
    • Faraday's law
    • Coulomb's law

  8. Which law states that the direction of an induced current opposes the change causing it?

    • Lenz's law
    • Maxwell's law
    • Fleming's rule
    • Faraday's law

  9. What magnetic force acts on a charge of 2 C moving at 3 m/s in 4 T?

    • 24 N
    • 8 N
    • 12 N
    • 6 N

  10. What is the magnetic flux through a half square metre coil perpendicular to two tesla?

    • 2.5 Wb
    • 1.0 Wb
    • 4.0 Wb
    • 0.25 Wb

  11. Which particle speed passes undeflected through perpendicular fields of 600 volts per metre and 0.2 tesla?

    • 1200 m/s
    • 120 m/s
    • 3000 m/s
    • 300 m/s

  12. What e.m.f. magnitude is induced in a 100-turn coil when flux changes by 0.02 Wb in 0.1 seconds?

    • 0.2 V
    • 2 V
    • 20 V
    • 200 V

  13. An ideal transformer has 200 primary turns and 50 secondary turns. Find Vs when Vp is 240 volts.

    • 960 V
    • 30 V
    • 120 V
    • 60 V

  14. What is the primary reason for constructing a transformer core using thin iron laminations?

    • Reduce eddy currents
    • Increase magnetic flux
    • Prevent overheating entirely
    • Soften the iron

  15. Which observation from the alpha-scattering experiment provided evidence for a tiny, dense nucleus?

    • Most particles absorbed
    • Continuous small deflections
    • Few large deflections
    • All particles reflected

  16. What is the order of magnitude for the ratio of atomic radius to nuclear radius?

    • 100000
    • 100
    • 1000
    • 1000000

  17. How is the orbit radius r of a charged particle related to its momentum p in field B?

    • r = B Q p
    • r = B Q / p
    • r = p / (B Q)
    • r = p B / Q

  18. If the speed of a charged particle doubles in a uniform magnetic field, its period will:

    • Halve
    • Double
    • Quadruple
    • Remain unchanged

  19. Using a balance and current-carrying wire, which expression correctly calculates magnetic flux density B?

    • B = m I / (g L)
    • B = m g / (I L)
    • B = m g I L
    • B = I L / (m g)

  20. An ideal transformer output is 12 watts at 6 volts. What primary current flows at 240 volts?

    • 0.5 A
    • 2.0 A
    • 20 A
    • 0.05 A

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