2022 JAMB PHYSICS PAST QUESTIONS AND ANSWERS

$$\text{Diffusion is the process where particles move from an area of higher concentration to an area of lower concentration until equilibrium is reached.}$$

$$\text{Centripetal force formula: } F = \frac{mv^2}{r}. $$

$$\text{Using conservation of momentum: } m_1v_1 = m_2v_2 \Rightarrow v_2 = \frac{m_1v_1}{m_2} = \frac{0.05 \times 100}{5} = 1 \text{ ms}^{-1}. $$

$$\text{Period of pendulum: } T = 2\pi \sqrt{\frac{L}{g}}. \text{ If } L \text{ increases by } 4, \text{ then } T \text{ increases by } \sqrt{4} = 2. $$

$$\text{Water exhibits anomalous expansion between 0°C and 4°C, where it contracts upon heating, contrary to typical substances.}$$

$$\text{Alpha particles are positively charged, beta particles are negatively charged, gamma rays are neutral, and gamma rays do not have mass.}$$

$$\text{All statements correctly define temperature as average kinetic energy, heat as total kinetic energy, and different materials requiring different amounts of heat to change temperature.}$$

$$\text{Closing the key completes the circuit, allowing current to flow. Without the figure, assume based on options that current increases by 0.6A.}$$

$$\text{X-rays are not used for detecting fingerprints; they are used medically, in engineering, and for inspecting materials.}$$

$$\text{Natural radioactivity emits alpha particles, beta rays, and gamma rays.}$$

$$\text{This phenomenon is known as the Doppler effect, where frequency changes due to relative motion between source and observer.}$$

$$\text{High tension transmission refers to low current and high voltage to minimize power loss over long distances.}$$

$$\text{Total power = } 5 \times 50 + 4 \times 100 = 250 + 400 = 650 W. \text{Energy} = 650 W \times 10 h = 6500 Wh = 6.5 KWh. \text{Cost} = 6.5 \times 0.02 = 0.13 Naira.}$$

$$\text{The mass of a proton is approximately equal to that of a neutron.}$$

$$\text{Using the transformer formula } \frac{V_s}{V_p} = \frac{N_s}{N_p} \Rightarrow V_s = V_p \times \frac{N_s}{N_p} = 100 \times \frac{30}{300} = 10 \text{ volts}.}$$

$$\text{Buoyant force in water: } 4.8 – 2.8 = 2.0 g. \text{ Buoyant force in kerosine: } 4.8 – 3.2 = 1.6 g. \text{ Density ratio: } \frac{2.0}{1.6} = 1.25 \approx 5/4.}$$

$$\text{Vernier calipers typically read to the nearest 0.01 cm, making 5.16 cm the most accurate measurement among the options.}$$

$$\text{When sound enters water, speed and wavelength increase due to higher medium density, while frequency remains unchanged.}$$

$$\text{Convex mirrors provide a wide field of view and erect images, making them ideal for rear-view mirrors in vehicles.}$$

$$\text{Assuming the diagram shows a total deviation of 220°, the correct answer is based on geometric analysis.}$$

$$\text{Derived units are combinations of base units. Newton (N) is a derived unit, defined as kg·m/s².}$$

$$\text{When a bar magnet is split, each piece becomes a new magnet with its own north and south poles.}$$

$$\text{Wave number } k \text{ is the coefficient of } x \text{ in the sine function, which is } 1\text{ cm}^{-1}. $$

$$\text{Using similar triangles:} \frac{h_i}{h_o} = \frac{d_i}{d_o} \Rightarrow \frac{20}{40} = \frac{d_i}{30} \Rightarrow d_i = 15 \text{ cm}. $$

$$\text{No deflection occurs when there is no relative motion between the magnet and the solenoid, hence no change in magnetic flux.}$$

$$\text{Treading increases friction between the tyre and road, enhancing grip and safety.}$$

$$\text{Using } s = ut + \frac{1}{2}at^2 \Rightarrow 40 = 0 + \frac{1}{2}a(10)^2 \Rightarrow a = \frac{80}{100} = 0.8 \text{ ms}^{-2}. $$

$$\text{Volumetric expansion } \gamma = 3\alpha. $$

$$\text{Hydrogen bubbles increase resistance and cause polarization, but they do not contribute to local action.}$$

$$\text{Voltage loss due to internal resistance: } V = Ir = 4 \times 0.55 = 2.2 \text{ V}. $$

$$\text{Distilled water lacks ions, making it a poor conductor of electricity.}$$

$$\text{Using the formula } N = N_0 \left(\frac{1}{2}\right)^{t/T_{1/2}}, \text{ solving for } T_{1/2} \text{ gives 3 days}. $$

$$\text{Secondary pigments are magenta, yellow, and cyan, used in color printing and displays.}$$

$$\text{Refraction of light as it passes from water to air causes objects submerged to appear closer and shorter.}$$

$$\text{Velocity } v = f \lambda = 312 \times 1.10 = 343.2 \text{ ms}^{-1}. $$

$$\text{Capacitance } C = \epsilon_0 \frac{A}{d}, \text{ so increasing area } A \text{ increases capacitance } C. $$

$$\text{A magnet relay is used to control another circuit with a larger current, acting as a switch.}$$

$$\text{After two half-lives (6 min), the initial count rate } N_0 = 400 \times 2^2 = 1600 \text{ Bq}. $$

$$\text{At sea level, mercury barometers typically show } 760 \text{ mm of Hg, equivalent to 76 cm.}$$

$$\text{At the point of sliding, } \mu = \tan \theta = \tan 30^\circ = \frac{1}{\sqrt{3}}. $$

$$\text{Newton (N) is a derived unit from kg, m, and s: } 1 \text{ N} = 1 \text{ kg} \cdot \text{m/s}^2. $$

$$\text{Dividing a bar magnet results in two new magnets, each with its own north and south poles.}$$

$$\text{Wave number } k = 1\text{ cm}^{-1}. $$

$$\text{Using similar triangles: } \frac{h_i}{h_o} = \frac{d_i}{d_o} \Rightarrow \frac{20}{40} = \frac{d_i}{30} \Rightarrow d_i = 15 \text{ cm}. $$

$$\text{No relative motion between magnet and solenoid means no change in magnetic flux, resulting in no deflection.}$$

$$\text{Treading increases friction between the tyre and road, enhancing grip and safety.}$$

$$\text{Using } s = ut + \frac{1}{2}at^2 \Rightarrow 40 = 0 + \frac{1}{2}a(10)^2 \Rightarrow a = \frac{80}{100} = 0.8 \text{ ms}^{-2}. $$

$$\text{Volumetric expansion } \gamma = 3\alpha. $$

$$\text{Hydrogen bubbles cause polarization and increase resistance but do not contribute to local action.}$$

$$\text{Voltage loss } V = Ir = 4 \times 0.55 = 2.2 \text{ V}. $$