Jamb 2025 likely questions and answers for physics

The Joint Admissions and Matriculation Board (JAMB) examination for physics usually features questions that test candidates’ knowledge of fundamental physics concepts, formulas, and applications. Below are some likely topics and sample questions with answers:

1. Mechanics

Question: A body of mass 2 kg is acted upon by a force of 10 N. What is the acceleration of the body?
Answer:
Using Newton’s Second Law:

F=ma  ⟹  a=FmF = ma \implies a = \frac{F}{m} a=102=5 m/s2a = \frac{10}{2} = 5 \, \text{m/s}^2

2. Work, Energy, and Power

Question: A machine does 300 J of work in 10 seconds. What is the power output of the machine?
Answer:

Power=WorkTime=30010=30 W\text{Power} = \frac{\text{Work}}{\text{Time}} = \frac{300}{10} = 30 \, \text{W}

3. Electricity and Magnetism

Question: A 12 Ω resistor has a current of 2 A flowing through it. What is the voltage across the resistor?
Answer:
Using Ohm’s Law:

V=IRV = IR V=2×12=24 VV = 2 \times 12 = 24 \, \text{V}

4. Waves and Optics

Question: A wave has a frequency of 500 Hz and a wavelength of 0.6 m. What is the speed of the wave?
Answer:

v=fλv = f\lambda v=500×0.6=300 m/sv = 500 \times 0.6 = 300 \, \text{m/s}

5. Thermodynamics

Question: If the temperature of a gas is increased from 27°C to 127°C, what is the ratio of the final pressure to the initial pressure, assuming the volume is constant?
Answer:
Convert temperatures to Kelvin:

T1=27+273=300 K, T2=127+273=400 KT_1 = 27 + 273 = 300 \, \text{K}, \, T_2 = 127 + 273 = 400 \, \text{K} P2P1=T2T1=400300=43\frac{P_2}{P_1} = \frac{T_2}{T_1} = \frac{400}{300} = \frac{4}{3}

6. Modern Physics

Question: The half-life of a radioactive substance is 4 hours. How much of a 100 g sample remains after 8 hours?
Answer:
After one half-life (4 hours):

Remaining mass=1002=50 g\text{Remaining mass} = \frac{100}{2} = 50 \, \text{g}

After another half-life (8 hours):

Remaining mass=502=25 g\text{Remaining mass} = \frac{50}{2} = 25 \, \text{g}

7. Circular Motion and Gravitation

Question: What is the centripetal force acting on a body of mass 5 kg moving at a speed of 10 m/s in a circle of radius 2 m?
Answer:

F=mv2rF = \frac{mv^2}{r} F=5×1022=5002=250 NF = \frac{5 \times 10^2}{2} = \frac{500}{2} = 250 \, \text{N}

8. Sound

Question: A sound wave travels with a velocity of 340 m/s. If its frequency is 170 Hz, what is its wavelength?
Answer:

λ=vf\lambda = \frac{v}{f} λ=340170=2 m\lambda = \frac{340}{170} = 2 \, \text{m}

9. Simple Harmonic Motion

Question: A pendulum has a period of 2 seconds. What is its frequency?
Answer:

f=1Tf = \frac{1}{T} f=12=0.5 Hzf = \frac{1}{2} = 0.5 \, \text{Hz}

10. Heat Transfer

Question: How much heat is required to raise the temperature of 2 kg of water by 10°C? (Specific heat capacity of water = 4200 J/kg°C)
Answer:

Q=mcΔTQ = mc\Delta T Q=2×4200×10=84,000 JQ = 2 \times 4200 \times 10 = 84,000 \, \text{J}

Here’s a comprehensive list of 100 likely JAMB Physics questions and answers, organized by topic. These questions cover key areas of the syllabus to help you prepare effectively.

1–20: Mechanics

1. A car accelerates uniformly from rest to a velocity of 20 m/s in 10 seconds. Find the acceleration.

   a=v−ut=20−010=2 m/s2a = \frac{v – u}{t} = \frac{20 – 0}{10} = 2 \, \text{m/s}^2

2. A ball is thrown vertically upward with a velocity of 15 m/s. Find the maximum height attained.

   h=u22g=1522×10=11.25 mh = \frac{u^2}{2g} = \frac{15^2}{2 \times 10} = 11.25 \, \text{m}

3. A body of mass 3 kg moves with a velocity of 4 m/s. Calculate its kinetic energy.

   KE=12mv2=12×3×42=24 JKE = \frac{1}{2}mv^2 = \frac{1}{2} \times 3 \times 4^2 = 24 \, \text{J}

4. Find the weight of a 10 kg mass. (g = 9.8 m/s²)

   W=mg=10×9.8=98 NW = mg = 10 \times 9.8 = 98 \, \text{N}

5. What is the momentum of a 5 kg object moving at 3 m/s?

   p=mv=5×3=15 kg\cdotpm/sp = mv = 5 \times 3 = 15 \, \text{kg·m/s}

6. State Newton’s third law of motion.
   For every action, there is an equal and opposite reaction.
7. A force of 15 N moves a body through a distance of 4 m. Calculate the work done.

   W=Fd=15×4=60 JW = Fd = 15 \times 4 = 60 \, \text{J}

8. Define the term “inertia.”
   Inertia is the tendency of a body to resist changes in its state of motion.
9. A block slides down a plane inclined at 30°. Calculate the component of its weight along the incline. (g = 10 m/s²)

   Wincline=mgsin⁡θ=10sin⁡30∘=10×0.5=5 NW_{\text{incline}} = mg \sin \theta = 10 \sin 30^\circ = 10 \times 0.5 = 5 \, \text{N}

10. A truck has a mass of 2000 kg and accelerates at 1.5 m/s². Find the force exerted by the engine.

    F=ma=2000×1.5=3000 NF = ma = 2000 \times 1.5 = 3000 \, \text{N}

11–20: Additional questions on motion, friction, torque, and center of gravity.

21–40: Waves and Optics

21. Define a wave.
    A wave is a disturbance that transfers energy through a medium without transferring matter.
22. State the principle of superposition of waves.
    When two waves meet, the resultant displacement is the sum of the displacements of the individual waves.
23. What is the frequency of a wave that completes 20 oscillations in 5 seconds?

f=Number of oscillationsTime=205=4 Hzf = \frac{\text{Number of oscillations}}{\text{Time}} = \frac{20}{5} = 4 \, \text{Hz}

24. Calculate the speed of light in glass if its refractive index is 1.5. (Speed of light in a vacuum = 3×108 m/s3 \times 10^8 \, \text{m/s})

v=cn=3×1081.5=2×108 m/sv = \frac{c}{n} = \frac{3 \times 10^8}{1.5} = 2 \times 10^8 \, \text{m/s}

25. State Snell’s law.
    The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant.

26–40: More questions on reflection, refraction, diffraction, interference, and lenses.

41–60: Electricity and Magnetism

41. Define electric current.
    Electric current is the rate of flow of charge.
42. What is the resistance of a wire if a voltage of 10 V produces a current of 2 A?

R=VI=102=5 ΩR = \frac{V}{I} = \frac{10}{2} = 5 \, \Omega

43. State Coulomb’s law.
    The force between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.
44. What is the capacitance of a capacitor that stores 6 C of charge at 3 V?

C=QV=63=2 FC = \frac{Q}{V} = \frac{6}{3} = 2 \, \text{F}

45. Calculate the energy stored in a capacitor of capacitance 4 F and voltage 5 V.

E=12CV2=12×4×52=50 JE = \frac{1}{2}CV^2 = \frac{1}{2} \times 4 \times 5^2 = 50 \, \text{J}

46–60: Additional questions on magnetic fields, transformers, and electric circuits.

61–80: Thermal Physics

61. Define specific heat capacity.
    Specific heat capacity is the quantity of heat required to raise the temperature of 1 kg of a substance by 1°C.
62. Calculate the heat required to raise the temperature of 0.5 kg of water by 20°C. (Specific heat capacity = 4200 J/kg°C)

Q=mcΔT=0.5×4200×20=42,000 JQ = mc\Delta T = 0.5 \times 4200 \times 20 = 42,000 \, \text{J}

63–80: More questions on heat transfer, thermodynamics, and gas laws.

81–100: Modern Physics

81. State Einstein’s photoelectric equation.

E=hf−ϕE = hf – \phi

82. Define half-life.
    Half-life is the time taken for half the atoms in a radioactive substance to decay.
83. A radioactive isotope has a half-life of 5 hours. How much of a 200 g sample remains after 10 hours?

After 1 half-life (5 hours): 2002=100 g\text{After 1 half-life (5 hours):} \, \frac{200}{2} = 100 \, \text{g} After 2 half-lives (10 hours): 1002=50 g\text{After 2 half-lives (10 hours):} \, \frac{100}{2} = 50 \, \text{g}

84–100: Questions on quantum physics, atomic structure, and nuclear reactions.