JAMB Physics 2024
Questions & Answers

A student might incorrectly choose acceleration or deceleration if they confuse inertia with external applied forces, or choose constant velocity thinking motion happens automatically. Newton’s first law, also known as the law of inertia, dictates that an object at rest maintains its stationary state unless acted upon by an external force, making this a fundamental principle in classical mechanics. Common mistake: Assuming an object requires a force to stay still rather than to change its state of motion.

Options suggesting energy can be created or destroyed, or that energy is always lost, misinterpret the absolute nature of physical laws. The principle of conservation of energy states that the total energy in an isolated system remains constant; it can neither be created nor destroyed, only transformed from one form to another. Common mistake: Believing energy can be lost entirely rather than converted into different forms within a system.

Geothermal, nuclear, or tidal energy might seem like major power drivers, but they are localized or secondary compared to the dominant planetary driver. Solar radiation from the sun serves as the primary source of energy driving Earth's climate system, directly influencing weather patterns and temperature. Common mistake: Confusing internal planetary energy sources with the external driver of global climate.

A student might miscalculate by omitting a variable or using incorrect acceleration values, leading to options like 50 J, 75 J, or 125 J. Potential energy is calculated using the formula PE = mgh, which multiplies the mass of 2 kg by the acceleration due to gravity of 10 ms^-2 and the height of 5 m, yielding 100 J. Common mistake: Incorrectly multiplying or omitting one of the parameters in the gravitational potential energy formula.

Options claiming an inverse relationship, no relationship, or equality confuse temperature scales with molecular speed metrics. The kinetic theory of gases states that the temperature of a gas is directly proportional to the average kinetic energy of its molecules, because temperature directly reflects the speed of molecular motion. Common mistake: Assuming temperature is equal to kinetic energy rather than directly proportional to its average value.

Students might mistakenly choose option A or C by confusing buoyancy rules with simple density comparisons. To reach the correct answer, consider what happens when a body is submerged: the upward buoyant force, also known as upthrust, exactly matches the weight of the displaced fluid. Common mistake: Confusing the buoyant force with the total weight of the object itself.

A student might incorrectly select option A by assuming all types of waves can propagate through empty space like light does. Analyzing wave classifications reveals that propagation depends on material oscillation, meaning these vibrations are mechanical waves and require a medium like air, water, or solids to travel. Common mistake: Assuming sound shares the same vacuum-traveling properties as electromagnetic waves.

One might mistakenly pick option A or B by miscalculating the difference in velocity or dividing incorrectly. To find the acceleration, divide the change in velocity by the time interval, computed as (15 - 0) / 3, which results in 5 ms^-2. Common mistake: Incorrectly substituting the velocity and time values into the kinematic formula.

A student could mistakenly choose option A or B by misinterpreting how distance scales the gravitational force. Newton’s law of universal gravitation establishes that the attractive force is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Common mistake: Forgetting that the distance factor is squared in the inverse relationship.

A learner might mistakenly select option B by confusing transformers with inverters or rectifiers used in power conversion. Examining circuit components shows that a transformer is utilized to step up or step down voltage in an AC circuit, relying on the turns ratio of its coils. Common mistake: Confusing the regulation of voltage levels with the conversion of current types like AC to DC.

Someone might mistakenly select option C by assuming wave interference is always constructive. The principle of superposition dictates that when two or more waves overlap, the resultant displacement at any point is simply the algebraic sum of the displacements of the individual waves at that point. Common mistake: Forgetting that overlapping waves can cancel each other out destructively rather than always reinforcing.

A student could mistakenly pick option A or B by dividing instead of multiplying the given values. Multiplying the frequency of 50 Hz by the wavelength of 2 m yields the speed of the wave, calculated as 50 * 2 = 100 ms^-1. Common mistake: Mixing up wave formula variables and dividing frequency by wavelength instead of multiplying them.

A student might mistakenly choose option A by assuming disordered systems naturally become more orderly over time. The second law of thermodynamics establishes that the entropy, or disorder, of an isolated system tends to increase over time, driving a natural progression toward equilibrium. Common mistake: Assuming entropy decreases or stays constant in isolated systems over time.

One might mistakenly pick option A, B, or D by confusing exhaustible fossil fuels with sustainable alternatives. Solar energy is classified as renewable because it comes from the sun, a resource that is replenished daily, unlike coal, natural gas, and petroleum. Common mistake: Treating finite fossil fuels as sustainable energy sources.

A student might mistakenly select option A or B by viewing light strictly through classical mechanics or geometric optics. The wave-particle duality reveals that light exhibits both wave-like properties, such as interference and diffraction, and particle-like properties, such as photons observed in the photoelectric effect. Common mistake: Limiting the behavior of light to either solely a wave or solely a particle.

A student could mistakenly pick option A or B by miscalculating the acceleration due to gravity or missing a factor in the multiplication. The work done against gravity is calculated using the formula W = mgh, substituting 3 kg for mass, 10 ms^-2 for gravity, and 4 m for height to get 3 * 10 * 4 = 120 J. Common mistake: Forgetting to multiply all three parameters (mass, gravity, and height) together.

One might mistakenly choose option A or D by confusing direct proportionality with inverse relationships among circuit variables. Ohm’s law establishes that the current through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance, which is expressed mathematically as V = IR. Common mistake: Inverting the relationship between voltage and current.

A student might mistakenly select option A or C by confusing atmospheric measurement tools with temperature or humidity instruments. A barometer is the specific device utilized to measure atmospheric pressure, frequently employing mercury or aneroid mechanisms. Common mistake: Confusing barometers with thermometers or hygrometers.

A learner could mistakenly choose option A or B by assuming momentum always dissipates or builds up automatically. The principle of conservation of momentum specifies that the total momentum of an isolated system remains constant if no external forces like friction or air resistance act on it. Common mistake: Forgetting that external forces can alter system momentum if not isolated.

A student might mistakenly select option C or D by incorrectly multiplying voltage and resistance instead of dividing them. Applying Ohm's law, the current flowing through the resistor is found by dividing the 12 V voltage by the 6 ̉ resistance, yielding I = 12 / 6 = 2 A. Common mistake: Multiplying voltage by resistance instead of dividing voltage by resistance.

Someone might mistakenly choose option A by assuming light speed changes relative to a moving frame of reference. Einstein’s theory of relativity dictates that the speed of light in a vacuum is constant at approximately 3 x 10^8 ms^-1 and does not depend on the motion of the observer or the source. Common mistake: Assuming the speed of light is relative to the observer's motion.

A student might mistakenly pick option A or C by confusing magnifying or flat mirrors with safety viewing optics. A convex mirror is deployed in a car's rearview mirror because it offers a wider field of view while forming upright, diminished images. Common mistake: Choosing a concave or plane mirror instead of a convex one for wide-angle viewing.

A student could mistakenly choose option A or C by assuming identical quantum states or shared spins are permitted for atomic electrons. The Pauli exclusion principle dictates that no two electrons in an atom can share the same set of four quantum numbers, which forces electrons into different orbitals. Common mistake: Assuming electrons can occupy identical quantum states within an atom.

A student might mistakenly select option A or C by forgetting to convert Celsius temperatures to Kelvin before applying gas laws. Using Charles’ law where V_1/T_1 = V_2/T_2, convert initial and final temperatures to absolute scales (300 K and 327 K) to calculate V_2 as (2 * 327) / 300, resulting in 2.18 m^3, which rounds to 2.2 m^3. Common mistake: Using Celsius temperatures directly in gas law calculations instead of converting to Kelvin.

A student might mistakenly pick option A or B by confusing thermal or static magnetic placement with dynamic flux changes. Faraday’s law of electromagnetic induction states that an electric current is induced in a conductor when the magnetic flux through it changes over time. Common mistake: Assuming a stationary magnetic field without flux change can induce a current.

One might mistakenly choose option A, C, or D by incorrectly identifying properties that actually belong to electromagnetic radiation. Electromagnetic waves do not require a medium to propagate and can easily travel through a vacuum, which contrasts with mechanical waves. Common mistake: Assuming electromagnetic waves share the medium requirements of sound waves.

A student could mistakenly pick option A by confusing fluid speed dynamics with static pressure rules. The Bernoulli principle dictates that as the speed of a fluid increases, its pressure decreases, assuming constant elevation and density, which explains phenomena like airplane lift. Common mistake: Assuming faster fluid flow results in higher pressure.

A student might mistakenly choose option A or C by miscalculating the turns ratio or multiplying incorrectly. Using the transformer equation Vs/Vp = Ns/Np, substituting secondary turns of 100, primary turns of 500, and primary voltage of 200 V yields Vs = 200 * (1/5) = 40 V. Common mistake: Inverting the turns ratio when calculating secondary voltage.

A student might mistakenly pick option A or C by assuming heat or any random light frequency can liberate electrons. The photoelectric effect establishes that electrons are emitted from a metal surface only when light of a frequency above a certain threshold linked to the work function strikes it. Common mistake: Believing that light of any frequency can trigger electron emission.

A student could mistakenly choose option A or B by confusing standard fuel combustion or solar capture with atomic generation. Nuclear power plants create energy through nuclear fission, a process where heavy atomic nuclei split into smaller fragments, releasing massive amounts of energy. Common mistake: Confusing nuclear fission with radioactive decay or fossil fuel combustion.

Students might mistakenly choose option A if they confuse wave propagation with a stationary medium, or option C by wrongly associating wave properties with amplitude. The Doppler effect occurs when relative motion exists between the source and an observer, which changes the perceived frequency of a wave. This phenomenon is commonly experienced as the shift in pitch of a siren as it approaches or recedes. Common mistake: assuming that wave frequency itself actually changes at the source rather than just appearing different to an observer.

A student might mistakenly select option A or B by miscalculating or incorrectly adding the mass and velocity values instead of multiplying them. To find the momentum, apply the formula p = mv, where mass (m) is 4 kg and velocity (v) is 3 ms^-1, resulting in 4 * 3 = 12 kgms^-1. Common mistake: adding the mass and velocity values together instead of multiplying them.

A student might select option A or B by focusing solely on classical physics concepts or assuming atomic entities act exclusively as traditional waves or particles with deterministic paths. Quantum mechanics indicates that matter at the atomic scale displays both wave-like and particle-like characteristics, with physical properties like position and momentum governed by probabilities, as described by Heisenberg’s uncertainty principle. Common mistake: treating atomic particles as classical objects with exact, simultaneous trajectories and positions.

A student might mistakenly choose speed, distance, or time because they represent common scalar quantities encountered in everyday motion problems. Velocity is classified as a vector quantity because it incorporates both magnitude and direction, distinguishing it from speed which only possesses magnitude. Common mistake: failing to account for direction when categorizing physical quantities.

A student might mistakenly choose option A or C by confusing reflection rules with refraction or assuming surface irregularities alter the fundamental angle relationships. The law of reflection establishes that the angle of incidence equals the angle of reflection, with both angles measured relative to the normal at the point of incidence. Common mistake: measuring angles relative to the reflecting surface rather than the normal line.

A student might select option A, B, or C by making arithmetic errors or using incorrect kinematic equations when calculating final velocity. Using the kinematic equation v^2 = u^2 + 2gh, substituting u = 0, g = 10 ms^-2, and h = 8 m gives v^2 = 0 + 2 * 10 * 8 = 160, yielding v = √160 ≈ 12.65 ms^-1, where the closest option is 16 ms^-1. Common mistake: forgetting to take the square root of the v^2 value.

A student might mistakenly choose option A or C by confusing Snell's law with the law of reflection or assuming a fixed refraction pattern regardless of media. Snell’s law dictates that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant, matching the ratio of the refractive indices of the two media (n_1 sinθ_1 = n_2 sinθ_2). Common mistake: treating the angles themselves as having a constant ratio instead of their sines.

A student might mistakenly choose volt or ohm by confusing current units with potential difference or resistance units. The SI unit of electric current is the ampere (A), which measures the rate of flow of electric charge. Common mistake: mixing up current with potential difference (measured in volts).

A student might mistakenly choose option A or C by incorrectly squaring the resistance or failing to square the current in the power formula. The power dissipated is calculated using P = I^2 * R, where current (I) is 2 A and resistance (R) is 4 Ω, giving 2^2 * 4 = 16 W. Common mistake: multiplying the current by the resistance without squaring the current.

A student might select option A or B by misinterpreting conservation principles to mean creation or destruction is permissible under certain conditions. The law of conservation of charge asserts that the total electric charge in an isolated system remains constant, meaning charge can neither be created nor destroyed, only transferred. Common mistake: thinking that charge can be locally created or destroyed without accounting for the entire isolated system.