WAEC Physics 2001 past questions

Checked by the Skolra question team · Last updated 15 October 2026

Ten questions from the 2001 WAEC Physics paper, with answers and explanations. We hold 36 questions from this paper, and the Skolra app has all of them.

WAEC Physics 2001 questions and answers

1. 1.A screw jack with a Tommy bar of length 12cm is used to raise a car through a vertical height of 25cm by turning the Tommy bar through 50 revolutions. Calculate the approximate velocity ratio of the jack [$\pi = 3.142$]
   1. A
      120
   2. B
      200
   3. C
      151
      Correct
   4. D
      75
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   Answer: C

   The velocity ratio of a screw jack is the distance the effort moves divided by the distance the load moves in the same number of turns:

   Distance effort travels = 2πr × n = 2 × 3.142 × 12 × 50 = 3770.4 cm

   Distance load moves = 25 cm

   VR = 3770.4 / 25 ≈ 151

2. 2.The time rate of change of momentum is
   1. A
      power
   2. B
      impulse
   3. C
      force
      Correct
   4. D
      work done
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   Answer: C

   Newton's second law states that the net force on a body equals the time rate of change of its momentum:

   F = dp/dt = Δp/Δt

   This means force is the time rate of change of momentum. Impulse is force multiplied by time (Ft = Δp), not the rate of change.

3. 3.A piece of cloth appears green in sunlight. When held in red light, it will appear
   1. A
      yellow
   2. B
      black
      Correct
   3. C
      blue
   4. D
      red
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   Answer: B

   A green cloth appears green in sunlight because it reflects green light and absorbs all other colours.

   When placed under red light, there is no green light to reflect. The cloth absorbs the red light and reflects nothing, so it appears black.

4. 4.A spring balance,which is suspended from the roof of a lift, carries a mass of 1kg at its free end. If the lift accelerates upwards at 2.5ms^-2, determine the reading on the spring balance. [g = 10ms^-2]
   1. A
      7.5 N
   2. B
      2.5 N
   3. C
      12.5 N
      Correct
   4. D
      10.0 N
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   Answer: C

   When a lift accelerates upward, the apparent weight increases. Applying Newton's second law:

   R = m(g + a) = 1 × (10 + 2.5) = 12.5 N

   The spring balance therefore reads 12.5 N.

5. 5.The amplitude of the motion of a body performing simple harmonic motion decreases with time because
   1. A
      energy is continuously dissipated by resistive forces such as friction and air resistance
      Correct
   2. B
      the angular frequency increases as the amplitude falls
   3. C
      the restoring force increases in magnitude with each successive oscillation
   4. D
      the period of oscillation decreases steadily with time
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   Answer: A

   In a real (damped) oscillator, resistive forces such as air resistance and friction do negative work on the body during each cycle.

   This continuously removes mechanical energy from the system, so the amplitude decreases with time — a process called damping.

   The period and frequency remain approximately constant even as the amplitude decreases (for light damping).

6. 6.Which of the following statements about sound is correct?
   1. A
      Sound is a transverse wave
   2. B
      Sound can travel through a vacuum
   3. C
      Sound is a longitudinal wave that requires a material medium for propagation
      Correct
   4. D
      Sound travels faster in air than in water
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   Answer: C

   Sound is a mechanical, longitudinal wave — particles of the medium vibrate parallel to the direction of wave propagation.

   Because it is a mechanical wave, sound requires a material medium and cannot travel through a vacuum.

   Sound travels faster in denser media: approximately 340 ms⁻¹ in air and about 1480 ms⁻¹ in water.

7. 7.The magnitude of the gravitational force between two particles 0.10m apart is 10N. If the distance between them is increased to 0.20m, calculate the magnitude of the new force
   1. A
      1.0 N
   2. B
      40.0 N
   3. C
      2.5 N
      Correct
   4. D
      5.0 N
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   Answer: C

   Gravitational force obeys an inverse-square law: F ∝ 1/r².

   Therefore: F₁/F₂ = (r₂/r₁)²

   10/F₂ = (0.20/0.10)² = (2)² = 4

   F₂ = 10 ÷ 4 = 2.5 N

8. 8.The material used for constructing the core of an electromagnet is
   1. A
      Hard steel
   2. B
      Soft iron
      Correct
   3. C
      Steel
   4. D
      Copper
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   Answer: B

   The core of an electromagnet is made from soft iron because it is a magnetically soft material — it has high magnetic permeability (magnetises strongly) and very low retentivity (loses its magnetism quickly when the current is switched off).

   Steel and hard steel have high retentivity and are used for permanent magnets, not electromagnets. Copper is non-magnetic.

9. 9.Which of the following statements about magnetic lines of force is not correct?
   1. A
      The closer the lines, the stronger the magnetic field
   2. B
      They always form closed loops
   3. C
      Two lines of force can intersect at neutral points
      Correct
   4. D
      The tangent to a line at any point gives the direction of the magnetic field
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   Answer: C

   Magnetic lines of force never intersect anywhere — not even at neutral points. If two lines crossed, the magnetic field at that point would have two directions simultaneously, which is impossible.

   Options b, d, and d are all correct statements about magnetic field lines. Option c is the incorrect statement.

10. 10.Electrons passing through crystals are diffracted because they
    1. A
       travel at very high speeds
    2. B
       have wave-like properties
       Correct
    3. C
       have very small mass
    4. D
       are negatively charged particles
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    Answer: B

    Electrons passing through crystals are diffracted because they possess wave-like properties, as predicted by de Broglie's hypothesis of wave-particle duality.

    The de Broglie wavelength is given by λ = h/mv. For electrons accelerated through typical voltages, this wavelength is comparable to the spacing between atoms in a crystal lattice, so diffraction occurs — direct evidence of the wave nature of matter.

The questions come from past JAMB, WAEC and NECO papers. We use software to help write the answer options and explanations, and every answer is checked twice before it goes on the site. How we check

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Practise all 36 questions we hold from the 2001 paper, on a timed CBT screen

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