JAMB Physics 2017 past questions

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

Ten questions from the 2017 JAMB Physics paper, with answers and explanations. We hold 45 questions from this paper, and the Skolra app has all of them.

JAMB Physics 2017 questions and answers

1. 1.Under what conditions are cathode rays produced in a discharge tube?
   1. A
      At atmospheric pressure with no voltage applied
   2. B
      At very low gas pressure and a high voltage across the electrodes
      Correct
   3. C
      When the tube is filled with gas at high pressure and short-circuited
   4. D
      At high gas pressure and a low voltage across the electrodes
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   Answer: B

   Cathode rays (streams of electrons) are produced in a discharge tube when the enclosed gas is at very low pressure (close to vacuum) and a high potential difference is applied across the electrodes.

   At ordinary atmospheric pressure there are too many gas molecules for a stable electron stream to form, which is why the pressure must first be reduced.

2. 2.A man of mass 50kg ascends a flight of stains 5m high in 5 seconds. If acceleration due to gravity is 10ms^{-2} the power expended is
   1. A
      250W
   2. B
      100W
   3. C
      500W
      Correct
   4. D
      2500W
   Show answerHide answer

   Answer: C

   Power expended against gravity is P = mgh / t.

   P = (50 × 10 × 5) / 5 = 2500 / 5 = 500W.

   Forgetting to divide the work done by the time taken leaves the un-divided value, 2500W, which is the total work done, not the power.

3. 3.I. Refraction II. Interference III. Diffraction Which of the above properties are common to all waves?
   1. A
      I, II and III
      Correct
   2. B
      I only
   3. C
      I and II only
   4. D
      II and III only
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   Answer: A

   Refraction, interference and diffraction are all general wave behaviours: any wave, whether mechanical (like sound or water waves) or electromagnetic (like light), and whether transverse or longitudinal, shows all three.

   Polarisation is the one wave property that is NOT common to all waves — it applies only to transverse waves — but it is not one of the three listed here, so all three (I, II and III) apply.

4. 4.

   It is known that a neutron exists in a light atomic nucleus

   Which of the following also exists in the nucleus?

   1. A
      Alpha particle
   2. B
      Electron
   3. C
      Photon
   4. D
      Proton
      Correct
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   Answer: D

   The nucleus of a light atom is made up of protons and neutrons only — these are collectively called nucleons.

   Since a neutron is already stated to be present, the other nucleon that must also exist in the nucleus is the proton. Electrons orbit outside the nucleus and are not found inside it.

5. 5.

   A cell of internal resistance $2\,\Omega$ supplies current to a $6\,\Omega$ resistor. The efficiency of the cell is

   1. A
      33.3%
   2. B
      25%
   3. C
      80%
   4. D
      75%
      Correct
   Show answerHide answer

   Answer: D

   The useful power delivered to the external resistor, as a fraction of the total power produced, gives the efficiency: efficiency = R / (R + r) × 100%.

   With R = 6Ω and r = 2Ω: efficiency = 6/(6+2) × 100 = 75%.

   Dividing the internal resistance by the total instead of the external resistance is what produces the low 25% figure.

6. 6.Which of the following is a semiconductor
   1. A
      Silver
   2. B
      Aluminium
   3. C
      Silicon
      Correct
   4. D
      Copper
   Show answerHide answer

   Answer: C

   Silicon is a semiconductor: its ability to conduct lies between that of a good conductor and an insulator, and it can be doped to control its conductivity.

   Copper, aluminium and silver are all good metallic conductors, not semiconductors.

7. 7.The volume of a fixed mass of gas is 10cm³ when its pressure is 400cmHg. Determine the volume of the gas when its pressure is 200cmHg.
   1. A
      20cm³
      Correct
   2. B
      40cm³
   3. C
      5cm³
   4. D
      10cm³
   Show answerHide answer

   Answer: A

   At constant temperature, Boyle's law gives P₁V₁ = P₂V₂.

   V₂ = P₁V₁/P₂ = (400 × 10) / 200 = 20cm³.

   Since the pressure is halved, the volume must double from 10cm³ to 20cm³ — halving it instead of doubling it is the usual error.

8. 8.Under which of the following conditions is work done?
   1. A
      When a weightlifter holds a loaded bar stationary above his head
   2. B
      When a person pushes hard against a wall and the wall does not move
   3. C
      When a force moves an object through a distance in the direction of the force
      Correct
   4. D
      When a satellite moves at constant speed in a circular orbit around the earth
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   Answer: C

   Work is done only when a force produces a displacement in the direction of the force: W = Fd cosθ.

   Pushing a wall that does not move, holding a load stationary, and a satellite in circular orbit (where the centripetal force is always perpendicular to the motion) are all cases where the force acts but there is no displacement along it, so no work is done.

9. 9.Which of the following is not an electromagnetic radiation?
   1. A
      Gamma rays
   2. B
      Ultraviolet rays
   3. C
      X-rays
   4. D
      Sound waves
      Correct
   Show answerHide answer

   Answer: D

   X-rays, ultraviolet rays and gamma rays are all part of the electromagnetic spectrum: they are transverse waves that can travel through a vacuum.

   Sound waves are mechanical waves — they need a material medium (solid, liquid or gas) to travel and cannot cross a vacuum, so they are not electromagnetic radiation.

10. 10.Calculate the upthrust on an object of volume 50cm³ which is immersed in liquid of density 103kgm^-3 [g = 10ms^-2]
    1. A
       0.0515N
       Correct
    2. B
       0.515N
    3. C
       5.15N
    4. D
       0.00515N
    Show answerHide answer

    Answer: A

    The upthrust on a fully immersed object equals the weight of the liquid it displaces, U = ρVg.

    Converting the volume: 50cm³ = 50 × 10^-6 m³. So U = 103 × (50 × 10^-6) × 10 = 0.0515N.

    Forgetting to convert cm³ to m³ before multiplying is what produces the much larger, wrong-looking values.

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 45 questions we hold from the 2017 paper, on a timed CBT screen

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