About this IB Physics practice test

IB Physics Paper 1 strips away intermediate working — a single tick is the whole mark, so spotting the physics behind a bad distractor is the real skill being tested. This set covers the full SL and HL syllabus, and every explanation spells out why each wrong option is wrong, not just why the right one is right.

IB Physics Practice Test sample questions

These starter questions help you launch a physics mock test quickly. Swap them with your own worksheet, notebook, or textbook questions any time.

1. 1. A ball is thrown horizontally at 10 m/s from a height of 20 m. How long does it take to reach the ground? (g = 10 m/s²)

2. A) 1 s

   • B) 2 s
   • C) 4 s
   • D) 5 s

3. 2. What is Newton's Third Law?

4. A) F = ma

   • B) Every action has an equal and opposite reaction
   • C) Objects at rest stay at rest
   • D) Force is proportional to extension

5. 3. A gas is compressed at constant temperature. What happens to its pressure?

6. A) Decreases

   • B) Increases
   • C) Stays the same
   • D) Depends on the gas type

7. 4. Two waves of equal amplitude interfere destructively. The path difference is:

8. A) nλ

   • B) (n + ½)λ
   • C) nλ/2
   • D) 2nλ

9. 5. A capacitor of capacitance 50 μF is charged to 10 V. Find the energy stored.

10. A) 2.5 mJ

    • B) 5 mJ
    • C) 25 mJ
    • D) 500 mJ

11. 6. What is the unit of electric field strength?

12. A) C/m

    • B) V·m
    • C) N/C
    • D) J/C

13. 7. An alpha particle consists of:

14. A) 2 protons, 2 neutrons

    • B) 1 proton, 1 neutron
    • C) 2 protons, 0 neutrons
    • D) 0 protons, 2 neutrons

15. 8. The threshold frequency in the photoelectric effect is:

16. A) the maximum frequency of emitted light

    • B) the minimum frequency needed to eject electrons
    • C) the frequency of the emitted electrons
    • D) the frequency at which stopping voltage is zero

17. 9. A wave has frequency 400 Hz and wavelength 0.85 m. Calculate its speed.

18. A) 170 m/s

    • B) 250 m/s
    • C) 340 m/s
    • D) 400 m/s

19. 10. Define half-life.

20. A) Time for half the atoms to gain a proton

    • B) Time for half the radioactive atoms in a sample to decay
    • C) Time for the activity to double
    • D) Half the time for complete decay

21. 11. A ball of mass 2 kg moving at 3 m/s collides head-on with a stationary ball of mass 1 kg. After the collision, the balls stick together. What is their common velocity?

22. A) 1 m/s

    • B) 2 m/s
    • C) 3 m/s
    • D) 6 m/s

23. 12. A car travels around a circular track at constant speed. Which statement about its motion is correct?

24. A) Its velocity is constant

    • B) Its acceleration is zero
    • C) Its acceleration is directed towards the centre of the circle
    • D) Its kinetic energy is changing

25. 13. A 0.5 kg object is dropped from rest and falls freely under gravity. Ignoring air resistance, what is its kinetic energy after falling 4 m? (g = 10 m/s²)

26. A) 5 J

    • B) 10 J
    • C) 20 J
    • D) 40 J

27. 14. An astronaut on the International Space Station experiences apparent weightlessness. This is because:

28. A) There is no gravitational force acting on the astronaut

    • B) The astronaut and station are in continuous free fall around Earth
    • C) The station is far enough from Earth that gravity is negligible
    • D) The astronaut's mass becomes zero in orbit

29. 15. How much energy is required to raise the temperature of 2 kg of water by 5°C? (specific heat capacity of water = 4200 J kg⁻¹ K⁻¹)

30. A) 4200 J

    • B) 8400 J
    • C) 21000 J
    • D) 42000 J

31. 16. A fixed mass of ideal gas is heated at constant volume. Which quantity remains unchanged?

32. A) Pressure

    • B) Temperature
    • C) Volume
    • D) Internal energy

33. 17. How much energy is needed to convert 0.2 kg of water at 100°C into steam at 100°C? (specific latent heat of vaporisation of water = 2.26 × 10⁶ J kg⁻¹)

34. A) 4.52 × 10⁴ J

    • B) 2.26 × 10⁵ J
    • C) 4.52 × 10⁵ J
    • D) 2.26 × 10⁶ J

35. 18. According to the kinetic theory of gases, the absolute temperature of an ideal gas is a direct measure of:

36. A) The pressure exerted by the gas

    • B) The average kinetic energy of the gas molecules
    • C) The total internal energy of the gas
    • D) The average speed of the gas molecules

37. 19. Two coherent sources emit waves of the same frequency. For constructive interference to occur at a point, the path difference must be:

38. A) An odd multiple of half a wavelength

    • B) A whole number multiple of the wavelength
    • C) Any value greater than zero
    • D) Exactly a quarter of the wavelength

39. 20. Monochromatic light of wavelength 600 nm is incident normally on a diffraction grating with 500 lines per mm. What is the angle of the first-order maximum?

40. A) 8.6°

    • B) 17.5°
    • C) 30°
    • D) 45°

41. 21. A police car with a siren sounding approaches a stationary observer and then passes by, moving away. Compared to the siren's actual frequency, the observer hears:

42. A) A higher frequency throughout

    • B) A lower frequency throughout
    • C) A higher frequency as it approaches, then a lower frequency as it moves away
    • D) The same frequency at all times

43. 22. A string fixed at both ends vibrates in its second harmonic. How many nodes (including the two fixed ends) are present?

44. A) 2

    • B) 3
    • C) 4
    • D) 5

45. 23. Two resistors of 6 Ω and 3 Ω are connected in parallel. What is their combined resistance?

46. A) 1 Ω

    • B) 2 Ω
    • C) 4.5 Ω
    • D) 9 Ω

47. 24. A bar magnet is pushed into a coil of wire connected to a sensitive ammeter. According to Lenz's law, the induced current in the coil acts to:

48. A) Increase the flux linkage of the coil

    • B) Oppose the motion of the magnet
    • C) Have no effect on the magnet's motion
    • D) Reverse the polarity of the magnet permanently

49. 25. An AC supply has a peak voltage of 340 V. What is the root-mean-square (rms) voltage?

50. A) 170 V

    • B) 200 V
    • C) 240 V
    • D) 340 V

51. 26. A charged capacitor is disconnected from its power source and connected across a resistor. As the capacitor discharges, the current in the circuit:

52. A) Remains constant

    • B) Increases exponentially
    • C) Decreases exponentially
    • D) Oscillates sinusoidally

53. 27. A radioactive sample has a half-life of 6 hours and an initial activity of 800 Bq. What is its activity after 18 hours?

54. A) 50 Bq

    • B) 100 Bq
    • C) 200 Bq
    • D) 400 Bq

55. 28. On a graph of binding energy per nucleon against nucleon number, the region of highest stability corresponds to nuclei with a mass number close to:

56. A) 2

    • B) 56
    • C) 120
    • D) 238

57. 29. In the de Broglie hypothesis, the wavelength associated with a moving particle is:

58. A) Directly proportional to its momentum

    • B) Inversely proportional to its momentum
    • C) Independent of its momentum
    • D) Proportional to the square of its momentum

59. 30. In a photoelectric effect experiment, increasing the intensity of incident light while keeping its frequency above the threshold frequency causes:

60. A) An increase in the maximum kinetic energy of emitted electrons

    • B) An increase in the number of photoelectrons emitted per second
    • C) A decrease in the work function of the metal
    • D) A decrease in the threshold frequency of the metal

Answer key & quick explanations

Short answers for the sample questions above. Use this to self-check before generating a fresh AI-built mock test.

1. 1. Projectile motion - time of flight

   B) 2 s

   Horizontal velocity does not affect vertical motion, so use h = ½gt². Solving 20 = ½(10)t² gives t² = 4, so t = 2 s. Option D (5 s) would result from incorrectly using h = gt² instead of ½gt².

2. 2. Newton's Third Law statement

   B) Every action has an equal and opposite reaction

   Newton's Third Law states that for every action force there is an equal and opposite reaction force acting on a different object. Option A (F = ma) is Newton's Second Law, and option C describes Newton's First Law (inertia).

3. 3. Isothermal compression - pressure change

   B) Increases

   At constant temperature, Boyle's Law (PV = constant) applies, so decreasing volume must increase pressure proportionally. The relationship does not depend on the specific gas, ruling out option D.

4. 4. Destructive interference - path difference

   B) (n + ½)λ

   Destructive interference occurs when two waves arrive exactly out of phase, which happens when the path difference is an odd multiple of half a wavelength, (n + ½)λ. A path difference of nλ (option A) instead produces constructive interference.

5. 5. Energy stored in a capacitor

   A) 2.5 mJ

   Energy stored is E = ½CV² = ½ × (50 × 10⁻⁶) × 10² = 2.5 × 10⁻³ J = 2.5 mJ. Option B (5 mJ) results from forgetting the factor of ½ in the formula.

6. 6. Unit of electric field strength

   C) N/C

   Electric field strength is force per unit charge, giving units of N/C (equivalently V/m). Option B, V·m, has the wrong dimensional relationship — multiplying rather than dividing potential by distance.

7. 7. Composition of an alpha particle

   A) 2 protons, 2 neutrons

   An alpha particle is identical to a helium-4 nucleus, containing 2 protons and 2 neutrons and no electrons. Option C (2 protons, 0 neutrons) would describe a nucleus that is not a stable alpha particle.

8. 8. Threshold frequency definition

   B) the minimum frequency needed to eject electrons

   The threshold frequency is the minimum frequency of incident light that provides enough photon energy (hf) to overcome the metal's work function and release an electron. Below this frequency, no photoelectrons are emitted regardless of intensity, which rules out option A.

9. 9. Wave speed from frequency and wavelength

   C) 340 m/s

   Wave speed is given by v = fλ = 400 Hz × 0.85 m = 340 m/s. Option D (400 m/s) incorrectly ignores the wavelength factor.

10. 10. Definition of half-life

    B) Time for half the radioactive atoms in a sample to decay

    Half-life is defined as the time taken for half of the radioactive nuclei in a sample to undergo decay, independent of the initial sample size. Option D confuses this with a fixed decay time rather than a proportional decay.

11. 11. Perfectly inelastic collision - final velocity

    B) 2 m/s

    Momentum is conserved: total initial momentum = (2 kg)(3 m/s) + (1 kg)(0) = 6 kg·m/s. Since the balls stick together, combined mass is 3 kg, giving v = 6/3 = 2 m/s. Option C (3 m/s) incorrectly assumes the moving ball's velocity is unchanged.

12. 12. Direction of centripetal acceleration

    C) Its acceleration is directed towards the centre of the circle

    Constant speed means velocity's magnitude is unchanged, but its direction constantly changes, producing a centripetal acceleration directed towards the centre. Option A is wrong because velocity's direction is changing, and option D is wrong because kinetic energy (½mv²) depends only on speed, which is constant.

13. 13. Kinetic energy of a freely falling object

    C) 20 J

    By conservation of energy, KE gained equals the loss in gravitational PE: KE = mgh = 0.5 kg × 10 m/s² × 4 m = 20 J. Option B (10 J) would result from omitting the fall height factor.

14. 14. Apparent weightlessness in orbit

    B) The astronaut and station are in continuous free fall around Earth

    At ISS altitude, gravity is only slightly weaker than at Earth's surface, so options A and C are incorrect. Weightlessness is apparent because the station and astronaut both accelerate towards Earth at the same rate — continuous free fall while moving forward fast enough to maintain orbit.

15. 15. Specific heat capacity calculation

    D) 42000 J

    Using E = mcΔT = 2 kg × 4200 J kg⁻¹K⁻¹ × 5 K = 42000 J. Option C (21000 J) would result from using only 1 kg instead of 2 kg of water.

16. 16. Constant-volume heating of a gas

    C) Volume

    By definition, a constant-volume process keeps volume fixed while pressure and temperature both increase (Gay-Lussac's law, P/T = constant). Option D is incorrect because internal energy increases as the gas is heated, since the average kinetic energy of its molecules rises.

17. 17. Latent heat of vaporisation calculation

    C) 4.52 × 10⁵ J

    Energy needed is E = mL = 0.2 kg × 2.26 × 10⁶ J kg⁻¹ = 4.52 × 10⁵ J. Option B (2.26 × 10⁵ J) incorrectly omits the mass factor of 0.2 kg.

18. 18. Temperature and molecular kinetic energy

    B) The average kinetic energy of the gas molecules

    Kinetic theory shows absolute temperature is directly proportional to the average translational kinetic energy of the gas molecules. Option D is a common distractor because average speed depends on the square root of temperature (since KE = ½mv²), not directly on temperature.

19. 19. Condition for constructive interference

    B) A whole number multiple of the wavelength

    Constructive interference occurs when waves arrive in phase, which happens when the path difference equals a whole number of wavelengths, nλ. Option A describes the condition for destructive interference instead.

20. 20. Diffraction grating - first-order angle

    B) 17.5°

    The grating spacing is d = 1/(500 lines/mm) = 2 × 10⁻⁶ m = 2000 nm. Using dsinθ = nλ with n = 1: sinθ = 600/2000 = 0.3, so θ = arcsin(0.3) ≈ 17.5°. Option C (30°) would result from an arithmetic slip in the inverse sine calculation.

21. 21. Doppler effect for a passing siren

    C) A higher frequency as it approaches, then a lower frequency as it moves away

    As the source approaches, sound waves are compressed, raising the observed frequency; as it recedes, the waves are stretched, lowering the observed frequency. Options A and B are each only half correct, describing just one phase of the motion.

22. 22. Nodes in the second harmonic of a string

    B) 3

    In the second harmonic (n = 2), the string forms two loops with nodes at both fixed ends and one additional node in the middle, giving 3 nodes total. The first harmonic (fundamental) has only 2 nodes, at the ends.

23. 23. Parallel resistor combination

    B) 2 Ω

    For resistors in parallel, 1/R = 1/6 + 1/3 = 3/6 = 1/2, so R = 2 Ω. Option D (9 Ω) would result from incorrectly adding the resistances as if in series.

24. 24. Lenz's law and induced current direction

    B) Oppose the motion of the magnet

    Lenz's law states that the induced current flows in a direction that creates a magnetic field opposing the change in flux that produced it, which in turn opposes the motion of the magnet (consistent with conservation of energy). Option A is incorrect because opposing the flux change means resisting, not aiding, the increase in flux linkage.

25. 25. RMS voltage from peak voltage

    C) 240 V

    For a sinusoidal AC supply, Vrms = Vpeak/√2 = 340/1.414 ≈ 240 V. Option D (340 V) incorrectly treats the peak and rms values as equal.

26. 26. Current during capacitor discharge

    C) Decreases exponentially

    As a capacitor discharges through a resistor, both charge and current follow exponential decay, I = I₀e^(-t/RC). Option B is incorrect since current falls rather than rises as the capacitor loses charge.

27. 27. Radioactive decay after multiple half-lives

    B) 100 Bq

    18 hours corresponds to 18/6 = 3 half-lives. Activity halves each half-life: 800 → 400 → 200 → 100 Bq. Option C (200 Bq) corresponds to stopping after only 2 half-lives.

28. 28. Peak of the binding energy curve

    B) 56

    The binding energy per nucleon curve peaks around iron-56 (A ≈ 56), which is why iron is among the most stable nuclides. Option D (238, uranium) lies on the declining, less stable, high-mass end of the curve.

29. 29. De Broglie wavelength and momentum

    B) Inversely proportional to its momentum

    The de Broglie relation is λ = h/p, showing wavelength is inversely proportional to momentum. Option A reverses this relationship, which would incorrectly suggest faster, more massive particles have longer wavelengths.

30. 30. Effect of light intensity on photoelectric emission

    B) An increase in the number of photoelectrons emitted per second

    Increasing intensity means more photons strike the surface per second, ejecting more photoelectrons per second and increasing photocurrent. Option A is incorrect because the maximum kinetic energy of photoelectrons depends only on photon frequency (via KEmax = hf − φ), not on intensity.

Curriculum Mapping & Learning Guide

Use this breakdown to identify which skills each question tests and guide post-test review.

IB Physics units covered

1. Chapter 1: Mechanics: kinematics, Newton's Laws, energy, momentum, circular motion, gravitation
2. Chapter 2: Thermal Physics: specific heat, latent heat, ideal gas law, kinetic theory
3. Chapter 3: Waves: properties, superposition, interference, diffraction, Doppler, optics
4. Chapter 4: Electricity & Magnetism: circuits, capacitance, electromagnetic induction, AC
5. Chapter 5: Nuclear & Quantum: radioactivity, half-life, binding energy, photoelectric effect, wave-particle duality

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