WAEC Physics 2003 past questions

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

Ten questions from the 2003 WAEC Physics paper, with answers and explanations. We hold 47 questions from this paper, and the Skolra app has all of them.

WAEC Physics 2003 questions and answers

1. 1.Which of the following statements is true of ultra violet radiations? It
   1. A
      has a longer wavelength than visible light
   2. B
      is visible to the naked eye
   3. C
      causes ionization of gas molecules
      Correct
   4. D
      travels slower than visible light in a vacuum
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   Answer: C

   Ultra violet (UV) radiation is an electromagnetic wave with wavelength shorter than visible light (approximately 10–400 nm). UV radiation causes ionization of gas molecules because its photons carry enough energy to knock electrons out of atoms. All electromagnetic waves travel at c = 3×10⁸ m/s in a vacuum, so UV does not travel slower than visible light. Its wavelength is shorter (not longer) than visible light, and it is invisible to the naked eye.

2. 2.Which of the following instruments gives a pure note when sounded?
   1. A
      tuning fork
      Correct
   2. B
      guitar string
   3. C
      flute
   4. D
      drum
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   Answer: A

   A tuning fork vibrates at a single frequency and produces a pure note (a single sinusoidal tone with no overtones or harmonics).

   Musical instruments such as the flute, guitar, and drum produce a fundamental tone accompanied by overtones, resulting in a complex (not pure) note.

3. 3.The silvered surface in a vacuum flask reduces heat loos due to
   1. A
      convection
   2. B
      evaporation
   3. C
      conduction
   4. D
      radiation
      Correct
   Show answerHide answer

   Answer: D

   A vacuum flask has double walls with a vacuum between them to minimise heat loss by conduction and convection. The silvered inner surfaces reduce heat transfer by radiation: silver is a poor emitter and poor absorber of infrared radiation, so it reflects radiant heat back into the flask. Each mechanism is addressed separately — the vacuum handles conduction/convection, and the silvering specifically counteracts radiation losses.

4. 4.Which of the following factors does not affect the electric resistance of wire?
   1. A
      colour of the conductor
      Correct
   2. B
      nature of the material
   3. C
      temperature of the conductor
   4. D
      length of the conductor
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   Answer: A

   The resistance of a conductor is given by R = ρL/A, where ρ is the resistivity (dependent on the material), L is the length, and A is the cross-sectional area. Temperature also affects resistance (most conductors increase in resistance with temperature). The colour of the conductor is a superficial property with no physical bearing on how electrons flow through the material and therefore does not affect electrical resistance.

5. 5.Which of the following statement about force is correct ?
   1. A
      a force can change the velocity of a body
      Correct
   2. B
      a force acting on a body always produces visible motion
   3. C
      a force can only act through direct physical contact
   4. D
      a force always causes a change in the temperature of a body
   Show answerHide answer

   Answer: A

   By Newton's second law, a net force causes acceleration, which is a change in velocity.

   A force can change the speed, direction, or both of a moving body. It can also set a stationary body in motion.

   Forces such as gravity and electrostatic forces act at a distance without contact, and a force may not always produce motion (e.g., when balanced by an equal and opposite force).

6. 6.A current of 10A passes through a conductor for 10s, calculate the charge flowing through the conductor
   1. A
      1000 C
   2. B
      1 C
   3. C
      100 C
      Correct
   4. D
      10 C
   Show answerHide answer

   Answer: C

   Electric charge is related to current and time by: Q = I × t

   Q = 10 A × 10 s = 100 C.

7. 7.Bohr's atomic model proves most successful for the explanation of the. I. structure of the hydrogen atom; II. line spectra of the hydrogen atom; III. Multi-electron atoms. Which of the statements above is/are correct?
   1. A
      I, II and III
   2. B
      I only
   3. C
      II only
   4. D
      I and II only
      Correct
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   Answer: D

   Bohr's atomic model was specifically developed to explain the structure of the hydrogen atom (I) and successfully predicts the discrete line spectra of hydrogen (II) — including the Lyman, Balmer, and Paschen series — using quantised electron orbits. However, it fails for multi-electron atoms (III) because it cannot account for electron-electron interactions, spin, or the full quantum mechanical picture. Therefore only statements I and II are correct.

8. 8.The minimum energy required to remove an electron from an atom is known as
   1. A
      work function
   2. B
      threshold energy
   3. C
      activation energy
   4. D
      ionization energy
      Correct
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   Answer: D

   The ionization energy is the minimum energy required to completely remove an electron from an atom in its ground state, overcoming the electrostatic attraction between the electron and the nucleus.

   The work function refers specifically to the minimum energy needed to eject an electron from the surface of a metal in the photoelectric effect, while ionization energy applies to atoms in general.

9. 9.The horizontal floor of a water reservoir appears to be 1.0m deep when viewed vertically from above. If the refractive index of water is 1.35, calculate the real depth of the reservoir
   1. A
      1.35 m
      Correct
   2. B
      1.50 m
   3. C
      0.74 m
   4. D
      0.90 m
   Show answerHide answer

   Answer: A

   The refractive index relates real and apparent depth by:

   n = Real depth / Apparent depth

   Real depth = n × apparent depth = 1.35 × 1.0 = 1.35 m.

10. 10.The direction of induced current in a straight wire placed in magnetic field is determined by using
    1. A
       Ohm's law
    2. B
       Fleming's left-hand rule
    3. C
       Ampere's swimming rule
    4. D
       Fleming's right-hand rule
       Correct
    Show answerHide answer

    Answer: D

    Fleming's right-hand rule (the dynamo rule) is used to determine the direction of the induced current in a conductor moving through a magnetic field.

    The thumb points in the direction of motion, the index finger points in the direction of the field, and the middle finger points in the direction of the induced current.

    Fleming's left-hand rule applies to motors (direction of force on a current-carrying conductor in a field).

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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