JAMB Physics practice questions (CBT)
Fifteen objective questions in the style of the JAMB UTME Physics CBT: motion, energy, pressure, heat, gas laws, waves, lenses, electricity, radioactivity and modern physics, each with a worked solution.
Original questions written by Studoli tutors in the style of the JAMB UTME exam. They are not official past questions.
Timed mode
15 questions in 10 minutes, one question at a time. Your answers are marked when you submit or when the time runs out.
Topic: Dimensions
1. What are the dimensions of force?
Solution
A. MLT⁻²
- Force = mass × acceleration.
- Acceleration has dimensions LT⁻², so force is MLT⁻².
Topic: Motion
2. A car starts from rest and accelerates uniformly to 20 m/s in 5 s. How far does it travel?
Solution
D. 50 m
- Average velocity = (0 + 20) ÷ 2 = 10 m/s.
- Distance = average velocity × time = 10 × 5 = 50 m.
Topic: Energy
3. Find the kinetic energy of a 2 kg body moving at 3 m/s.
Solution
C. 9 J
- KE = ½mv².
- = ½ × 2 × 3² = 9 J.
Topic: Free fall
4. A stone is dropped from a height of 20 m. How long does it take to reach the ground? (g = 10 m/s²)
Solution
B. 2 s
- h = ½gt², so t = √(2h/g).
- t = √(2 × 20 ÷ 10) = √4 = 2 s.
Topic: Momentum
5. Find the momentum of a 5 kg mass moving at 4 m/s.
Solution
A. 20 kg m/s
- Momentum = mass × velocity.
- = 5 × 4 = 20 kg m/s.
Topic: Pressure
6. Find the pressure due to water at a depth of 10 m. (Density of water = 1000 kg/m³, g = 10 m/s²)
Solution
D. 1.0 × 10⁵ Pa
- P = hρg.
- = 10 × 1000 × 10 = 100,000 Pa = 1.0 × 10⁵ Pa.
Topic: Heat
7. How much heat is needed to raise the temperature of 2 kg of water by 10 °C? (Specific heat capacity of water = 4200 J/kg K)
Solution
C. 84,000 J
- Q = mcΔθ.
- = 2 × 4200 × 10 = 84,000 J.
Topic: Gas laws
8. A gas at 100 kPa occupies 6 L. It is compressed to 2 L at constant temperature. Find its new pressure.
Solution
B. 300 kPa
- Boyle's law: P₁V₁ = P₂V₂.
- 100 × 6 = P₂ × 2, so P₂ = 300 kPa.
Topic: Waves
9. A wave has a frequency of 50 Hz and a wavelength of 2 m. Find its speed.
Solution
A. 100 m/s
- v = fλ.
- = 50 × 2 = 100 m/s.
Topic: Lenses
10. An object is placed 15 cm from a converging lens of focal length 10 cm. Find the image distance.
Solution
D. 30 cm
- 1/f = 1/u + 1/v, so 1/v = 1/10 − 1/15.
- 1/v = 3/30 − 2/30 = 1/30.
- v = 30 cm (a real image on the other side of the lens).
Topic: Electricity
11. Find the combined resistance of 6 Ω and 3 Ω connected in parallel.
Solution
C. 2 Ω
- 1/R = 1/6 + 1/3 = 1/6 + 2/6 = 3/6.
- R = 6/3 = 2 Ω.
Topic: Electrical energy
12. A 2 kW heater is used for 3 hours. How much energy does it use?
Solution
B. 6 kWh
- Energy = power × time.
- = 2 kW × 3 h = 6 kWh.
Topic: Radioactivity
13. A radioactive sample of 64 g has a half-life of 4 days. How much remains after 12 days?
Solution
A. 8 g
- 12 days ÷ 4 days = 3 half-lives.
- 64 → 32 → 16 → 8 g.
Topic: Photoelectric effect
14. Photons of energy 5 eV fall on a metal with a work function of 2 eV. Find the maximum kinetic energy of the emitted electrons.
Solution
D. 3 eV
- Einstein's equation: KEmax = hf − W.
- = 5 − 2 = 3 eV.
Topic: Transformers
15. An ideal transformer has 100 turns on the primary and 500 turns on the secondary. The primary voltage is 240 V. Find the secondary voltage.
Solution
C. 1200 V
- Vs/Vp = Ns/Np.
- Vs = 240 × 500 ÷ 100 = 1200 V.