WAEC Physics 2000 past questions

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

Ten questions from the 2000 WAEC Physics paper, with answers and explanations. We hold 48 questions from this paper, and the Skolra app has all of them.

WAEC Physics 2000 questions and answers

1. 1.A nuclide $^{202}_{84} Y$ emits in succession an $\alpha-particle$ and a $\beta-particle$. The atomic number of the resulting nuclide is
   1. A
      85
   2. B
      83
      Correct
   3. C
      82
   4. D
      81
   Show answerHide answer

   Answer: B

   Starting nuclide: ²⁰²₈₄Y
   α-decay: atomic number decreases by 2 ⇒ Z = 84 − 2 = 82
   β-decay: atomic number increases by 1 ⇒ Z = 82 + 1 = 83
   The mass number after α-decay is 198, and β-decay does not change the mass number, so the final nuclide is ¹⁹⁸₈₃.

2. 2.A piece of metal of mass 50g is cooled from 80^oC to 20^oC. Calculate the amount of heat lost. (specific heat capacity of the material of metal = 450Jkg^-1K^-1)
   1. A
      2700 J
   2. B
      900 J
   3. C
      1350 J
      Correct
   4. D
      450 J
   Show answerHide answer

   Answer: C

   Heat lost: Q = mcΔT

   m = 50 g = 0.05 kg, c = 450 J kg⁻¹ K⁻¹, ΔT = 80 − 20 = 60 K

   Q = 0.05 × 450 × 60 = 1350 J

3. 3.A uniform metre rule of mass 90g is provided at the 40cm mark. If the rule is in equilibrium with an unknown mass m placed at the 10cm mark and a 72g mass at the 70cm mark, determine m
   1. A
      74 g
   2. B
      102 g
      Correct
   3. C
      82 g
   4. D
      96 g
   Show answerHide answer

   Answer: B

   Taking moments about the pivot at 40 cm: Anticlockwise moments = Clockwise moments

   Anticlockwise: m × (40 − 10) = 30m g·cm

   Clockwise:

   • Rule's weight (90 g) acts at its centre (50 cm): 90 × (50 − 40) = 900 g·cm
   • 72 g mass at 70 cm: 72 × (70 − 40) = 2160 g·cm

   30m = 900 + 2160 = 3060

   m = 102 g

4. 4.A nuclide represented as $^{70}_{32}X$ has a neutron-proton ratio of
   1. A
      35/16
   2. B
      16/19
   3. C
      19/16
      Correct
   4. D
      32/38
   Show answerHide answer

   Answer: C

   For ⁷⁰₃₂X:
   Proton number = 32
   Neutron number = 70 − 32 = 38
   Neutron-to-proton ratio = 38/32 = 19/16

5. 5.A wooden block of mass 1.6kg rest on a rough horizontal surface, if the limiting friction force between the block and the surface is 8N. Calculate the coefficient of friction. (g = 10ms^-2)
   1. A
      0.20
   2. B
      0.50
      Correct
   3. C
      0.80
   4. D
      0.40
   Show answerHide answer

   Answer: B

   The coefficient of limiting friction: μ = F / N

   Normal reaction N = mg = 1.6 × 10 = 16 N

   μ = 8 / 16 = 0.50

6. 6.the factor which enables the ear to distinguish between a note played on different instruments is the
   1. A
      Pitch
   2. B
      Amplitude
   3. C
      Quality
      Correct
   4. D
      Loudness
   Show answerHide answer

   Answer: C

   Different instruments playing the same note have the same fundamental frequency (pitch) and may have similar loudness, yet sound distinctly different. The ear distinguishes between them by the quality (timbre) of the sound.

   Quality depends on the number and relative intensities of the overtones (harmonics) present. Each instrument produces a unique harmonic mixture, giving it a characteristic tone colour.

7. 7.

   During the electrolysis of copper (II) tetraoxosulphate (VI) solution, a steady current of 4.0 x 10$^2$ A flowing for one hour liberated 0.48 g of copper. Calculate the mass of copper liberated by one coulomb of charge.

   1. A
      1.33 × 10⁻² g C⁻¹
   2. B
      1.67 × 10⁻³ g C⁻¹
   3. C
      6.67 × 10⁻³ g C⁻¹
   4. D
      3.33 × 10⁻³ g C⁻¹
      Correct
   Show answerHide answer

   Answer: D

   Total charge passed: Q = I × t = 4.0 × 10⁻² A × 3600 s = 144 C
   Mass liberated per coulomb = mass liberated / total charge
   = 0.48 g / 144 C = 3.33 × 10⁻³ g C⁻¹
   (This is the electrochemical equivalent of copper.)

8. 8.A simple microscope forms an image 10cm from an eye close to the lens. If the object is 6cm from the eye, calculate the focal length of the lens
   1. A
      15.0 cm
      Correct
   2. B
      3.75 cm
   3. C
      7.50 cm
   4. D
      60.0 cm
   Show answerHide answer

   Answer: A

   For a simple microscope the image is virtual and on the same side as the object.

   Using Cartesian sign convention: object distance u = −6 cm, image distance v = −10 cm.

   Lens formula: 1/f = 1/v − 1/u

   1/f = 1/(−10) − 1/(−6) = −1/10 + 1/6 = (−3 + 5)/30 = 2/30

   f = 15 cm

9. 9.The resultant of two forces acting on an object is maximum when the angle between them is
   1. A
      180°
   2. B
      45°
   3. C
      90°
   4. D
      0°
      Correct
   Show answerHide answer

   Answer: D

   The resultant of two forces F₁ and F₂ is: R = √(F₁² + F₂² + 2F₁F₂ cosθ)

   For R to be maximum, the term 2F₁F₂ cosθ must be maximum. This requires cosθ = 1, which occurs when θ = 0°.

   At 0°, both forces act in the same direction, giving R_max = F₁ + F₂.

10. 10.An object is situated within the Earth's gravitational field. Which of the following factor does not affect the acceleration of free fall g?
    1. A
       Distance from the centre of the Earth
    2. B
       Rotation of the Earth
    3. C
       Mass of the falling object
       Correct
    4. D
       Mass of the Earth
    Show answerHide answer

    Answer: C

    Acceleration due to gravity: g = GM/r²

    where G is the gravitational constant, M is the Earth's mass, and r is the distance from the Earth's centre.

    From this expression g depends on the mass of the Earth, the distance from the Earth's centre, and (to a small extent) the rotation of the Earth. The mass of the falling object does not appear in the formula and has no effect on g.

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

Spotted a wrong answer? Tell us from the app or on the contact page and we check it.

Practise all 48 questions we hold from the 2000 paper, on a timed CBT screen

Every question has the answer and an explanation, in the Skolra app.

Download for WindowsDownload for Mac

About the app · Skolra for Windows · Skolra for Mac