JAMB Physics 2022
Questions & Answers

One might mistakenly select an option suggesting force decreases with acceleration or operates independently, misinterpreting the proportionalities. By analyzing the mechanics of motion, pushing an object requires an effort tied directly to how heavy the item is and how fast it speeds up. When combining these variables mathematically, the force acting upon an object is directly proportional to the product of its mass and acceleration, typically written as F = ma. Common mistake: reversing the proportionalities between mass, acceleration, and force.

A student might incorrectly think that objects in motion naturally slow down or speed up without external triggers, confusing natural friction with fundamental laws. Looking at how objects behave fundamentally, stationary items and moving items share a common tendency to maintain their current velocity. Therefore, an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force, which describes the law of inertia as part of Newton's first law. Common mistake: assuming that moving objects naturally come to a halt on their own.

A student might incorrectly believe that energy can be created or destroyed, or that it is always lost as heat, failing to account for closed system dynamics. When evaluating closed systems, the total energy remains constant, only transforming from one form to another, such as kinetic to potential energy. Common mistake: forgetting that energy changes forms rather than being permanently destroyed or lost.

A person might mistakenly think gas molecules are completely stationary or travel only in straight lines without collisions, ignoring thermal effects. Looking at molecular behavior, gas molecules are in constant random motion, and their average kinetic energy is directly proportional to the absolute temperature of the gas. Common mistake: assuming temperature affects molecular motion only by changing collision frequency rather than average kinetic energy.

A student might mistakenly guess that an object sinks or floats simply based on whether its weight or density is greater than the fluid's without considering displacement. Analyzing submerged objects, the upward force experienced equals the weight of the fluid pushed aside. Thus, an object immersed in a fluid experiences an upward buoyant force equal to the weight of the fluid displaced. Common mistake: confusing the buoyant force with the total weight of the object itself.

A student might mistakenly think the gravitational force increases with distance or is independent of the masses involved, confusing inverse-square relations with linear ones. By examining gravitational interactions, the force relies on both the sizes of the objects and the separation space between them. Newton's law of universal gravitation states that the gravitational force between two masses is inversely proportional to the square of the distance between them and directly proportional to the product of their masses. Common mistake: thinking the gravitational force is directly proportional to the distance rather than inversely proportional to its square.

One might mistakenly select an option claiming natural processes decrease or conserve entropy, overlooking the natural tendency toward disorder. When observing isolated systems, spontaneous events progress in a specific direction that reduces usable energy. Consequently, natural processes in an isolated system tend to increase entropy, moving toward a state of maximum disorder. Common mistake: assuming that isolated systems maintain a constant level of entropy over time.

A student might mistakenly think that waves always cancel or always reinforce each other, ignoring how phase differences create varied outcomes. When examining wave behavior, overlapping waves combine their individual effects at every point. Therefore, the resultant displacement at any point is the sum of the displacements of the individual waves. Common mistake: assuming wave superposition always results in complete destructive interference.

A person might mistakenly believe that light and matter strictly exhibit only particle or only wave properties, ignoring experimental variations. Investigating microscopic phenomena reveals that both light and matter exhibit wave-like properties, such as interference, and particle-like properties, such as photons and electrons, depending on the experiment. Common mistake: assuming particles like electrons never display wave characteristics.

A student might mistakenly believe that voltage is independent of resistance or that resistance is directly proportional to current, misinterpreting circuit dependencies. By analyzing electrical circuits, the current through a conductor relies on both the applied electrical pressure and the opposition it faces. Specifically, the current (I) through a conductor is directly proportional to the voltage (V) across it and inversely proportional to its resistance (R), expressed as V = IR. Common mistake: inverting the relationship between current and resistance.

One might mistakenly believe that momentum naturally increases or decreases over time, forgetting about external influences like friction. Within an isolated system, the total momentum remains constant if no external forces act on it. Common mistake: failing to account for external forces when analyzing system momentum.

A student might mistakenly assume the speed of light varies depending on the observer's motion or the source's movement, applying classical relative velocity rules. In the framework of special relativity, measurements in a vacuum yield a constant speed of approximately 3 x 10^8 ms^-1 for all observers, regardless of their motion or the motion of the source. Common mistake: applying Galilean velocity addition to the speed of light.

A person might mistakenly think electrons can occupy the same quantum state or share identical sets of properties, ignoring atomic structure rules. Within an atom, no two electrons can have the same set of four quantum numbers, ensuring unique electron configurations through the Pauli exclusion principle. Common mistake: assuming electrons in the same orbital share identical quantum numbers.

A student might mistakenly think a current is induced by simply heating a conductor or keeping the magnetic field static. Looking at electromagnetic induction, electricity generation depends on a changing environment rather than a static one, meaning an electric current is induced in a conductor when the magnetic flux through it changes over time. Common mistake: assuming a stationary magnetic field can induce a continuous current.

A student might mistakenly believe that heating a metal or shining light of any frequency will trigger electron emission, ignoring threshold requirements. For electrons to leave a metal surface, the incoming light must possess adequate energy. The photoelectric effect states that electrons are emitted from a metal surface when light of a frequency above a threshold, related to the metal's work function, strikes it. Common mistake: assuming low-frequency light will eventually cause electron emission if left shining long enough.

One might mistakenly assume that wave frequency remains completely constant regardless of motion, ignoring the pitch shifts heard with moving sirens. When a source and an observer are in relative motion, the observed frequency of a wave changes, exemplified by the pitch of a siren changing as it passes by. Common mistake: confusing source frequency with the observed frequency during relative motion.

A student might mistakenly believe that atomic particles have completely definite positions and velocities simultaneously, overlooking probabilistic nature. At the microscopic level, particles exhibit both wave-like and particle-like behavior, with their properties described by probabilities, such as Heisenberg's uncertainty principle. Common mistake: treating quantum particles with classical certainty regarding position and trajectory.

A person might mistakenly think the angle of incidence is greater or less than the angle of reflection, confusing reflection with refraction. Measuring relative to the normal at the point of incidence, the law of reflection states that the angle of incidence is equal to the angle of reflection. Common mistake: measuring angles from the mirror surface instead of the normal line.

A student might mistakenly think the angle of refraction always equals the angle of incidence or is independent of it, ignoring medium density changes. When light passes between different media, the bending follows a specific mathematical ratio. Snell's law states that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant, equal to the ratio of the refractive indices of the two media. Common mistake: assuming the angles themselves are equal rather than their sines.

A person might mistakenly assume that pressure is inversely proportional to temperature or that volume is independent of temperature, ignoring ideal gas behavior. For an ideal gas, pressure (P), volume (V), and temperature (T) are related by PV = nRT, where n is the number of moles and R is the gas constant. Common mistake: omitting the number of moles or the gas constant when calculating gas states.