2021 JAMB PHYSICS PAST QUESTIONS AND ANSWERS Leave a Comment / Jamb Physics / By Jamb Tutor Report a question What’s wrong with this question? You cannot submit an empty report. Please add some details. 0% Created by Jamb TutorJamb Physics 2021 JAMB PHYSICS PAST QUESTIONS AND ANSWERS 1 / 40 Category: JAMB Physics 2021 1. Purpose of the vacuum in a thermos flask is to reduce heat loss by: a) Convection. b) Radiation. c) Conduction. d) Evaporation. Vacuum prevents heat transfer via convection by eliminating air molecules. 2 / 40 Category: JAMB Physics 2021 2. A body that emits light by itself is called: a) Luminous body. b) Non-luminous body. c) Opaque body. d) Transparent body. Luminous bodies emit light independently without external illumination. 3 / 40 Category: JAMB Physics 2021 3. Frictional force acting on 20 kg mass with $\mu = 0.5$ on horizontal surface: a) 80 N. b) 120 N. c) 100 N. d) 60 N. Force $= \mu mg = 0.5 \times 20 \times 10 = 100$ N. 4 / 40 Category: JAMB Physics 2021 4. Velocity for placing a satellite in orbit around Earth with radius $6.4 \times 10^6$ m: a) 11.3 ms$^{-1}$. b) 10.2 ms$^{-1}$. c) 12.5 ms$^{-1}$. d) 15.0 ms$^{-1}$. Orbital velocity $v = \sqrt{gR}$. Solve for $v = 11.3$ ms$^{-1}$. 5 / 40 Category: JAMB Physics 2021 5. Force on an electron with charge $1.6 \times 10^{-19}$ C moving at right angles in $B = 2.0 \times 10^{-4}$ T and $v = 1.5 \times 10^3$ ms$^{-1}$: a) $3.2 \times 10^{-5}$ N. b) $6.4 \times 10^{-5}$ N. c) $2.4 \times 10^{-5}$ N. d) $4.8 \times 10^{-5}$ N. Force $F = qvB$. Substitution gives $F = 4.8 \times 10^{-5}$ N. 6 / 40 Category: JAMB Physics 2021 6. The two processes essential in an air conditioning system are: a) Melting and freezing. b) Freezing and condensation. c) Evaporation and condensation. d) Evaporation and melting. Air conditioning involves evaporation to absorb heat and condensation to release it, controlling temperature. 7 / 40 Category: JAMB Physics 2021 7. Pressure at 200m swimming pool depth with $g = 10$ ms$^{-2}$, $\rho = 10^3$ kgm$^{-3}$, and atmospheric pressure $= 1.3 \times 10^6$ Nm$^{-2}$: a) $2.5 \times 10^6$ Nm$^{-2}$. b) $2.8 \times 10^6$ Nm$^{-2}$. c) $3.0 \times 10^6$ Nm$^{-2}$. d) $3.3 \times 10^6$ Nm$^{-2}$. Pressure $P = \rho gh + P_\text{atm}$. Solve for $P = 3.3 \times 10^6$ Nm$^{-2}$. 8 / 40 Category: JAMB Physics 2021 8. Spring constant when a force of 10 N produces an extension of 0.05 m: a) 100 Nm$^{-1}$. b) 150 Nm$^{-1}$. c) 200 Nm$^{-1}$. d) 250 Nm$^{-1}$. Hooke’s law $F = kx$. Solve for $k = \frac{F}{x} = 200$ Nm$^{-1}$. 9 / 40 Category: JAMB Physics 2021 9. Heat released when 0.1 kg of steam condenses to water at 100°C. Specific latent heat of vaporization is $2.2 \times 10^6$ Jkg$^{-1}$: a) $2.0 \times 10^5$ J. b) $1.8 \times 10^5$ J. c) $2.4 \times 10^5$ J. d) $2.2 \times 10^5$ J. Heat $Q = mL$. Substitution gives $Q = 0.1 \times 2.2 \times 10^6 = 2.2 \times 10^5$ J. 10 / 40 Category: JAMB Physics 2021 10. Cost of using a 200 W electric iron for 5 hours at ₦5.00 per kWh: a) ₦5.00. b) ₦10.00. c) ₦15.00. d) ₦20.00. Energy consumed = $\frac{200}{1000} \times 5 = 1$ kWh. Cost = 1 × 5 = ₦5.00. 11 / 40 Category: JAMB Physics 2021 11. Radiation with the highest penetrating power: a) Gamma rays. b) Beta rays. c) Alpha rays. d) X-rays. Gamma rays have the highest energy and penetration among electromagnetic radiation. 12 / 40 Category: JAMB Physics 2021 12. Power of a convex lens with focal length 20 cm: a) 4 D. b) 3 D. c) 2 D. d) 5 D. Power $P = \frac{100}{f}$. Solve for $P = \frac{100}{20} = 5$ D. 13 / 40 Category: JAMB Physics 2021 13. Power of a lift lifting 1000 kg lift with 650 kg people 40 m in 50 seconds: a) 132,000 W. b) 150,000 W. c) 140,000 W. d) 120,000 W. Power $P = \frac{(m_1 + m_2)gh}{t}$. Substitution gives $P = 132,000$ W. 14 / 40 Category: JAMB Physics 2021 14. Wavelength of air column in closed pipe resonating at 0.425 m: a) 1.60 m. b) 1.70 m. c) 1.80 m. d) 1.90 m. Wavelength $\lambda = 4l$. Solve for $\lambda = 4 \times 0.425 = 1.70$ m. 15 / 40 Category: JAMB Physics 2021 15. Principle underlying a beam balance: a) Conservation of energy. b) Principle of inertia. c) Law of motion. d) Principle of moments. Beam balance operates on the principle of moments, ensuring equilibrium between forces. 16 / 40 Category: JAMB Physics 2021 16. Placement of an object in front of a concave mirror to form a magnified, upright, and virtual image: a) Between the mirror and the focus. b) At the center of curvature. c) Beyond the center of curvature. d) At the focus. The object must be placed between the pole and the focus of the mirror. 17 / 40 Category: JAMB Physics 2021 17. Example of a secondary cell: a) Voltaic cell. b) Dry cell. c) Leclanché cell. d) Thermocouple. A secondary cell is rechargeable; an example is a voltaic cell. 18 / 40 Category: JAMB Physics 2021 18. Component of the visible spectrum with the longest wavelength when white light is dispersed: a) Red. b) Green. c) Violet. d) Blue. Red light has the longest wavelength among the visible spectrum. 19 / 40 Category: JAMB Physics 2021 19. Condition for resonance in an alternating current circuit: a) $X_L > X_C$. b) $X_L < X_C$. c) $X_L = R$. d) $X_L = X_C$. In resonance, the inductive reactance $X_L$ equals the capacitive reactance $X_C$. 20 / 40 Category: JAMB Physics 2021 20. Shortest distance for a rescue boat to reach a stranded boat after traveling due east and 60° northeast: a) 67.66 m. b) 60.00 m. c) 70.00 m. d) 75.00 m. Using the cosine rule, solve for the shortest distance as 67.66 m. 21 / 40 Category: JAMB Physics 2021 21. Definition of velocity ratio of a machine: a) I, II, and IV. b) I, II, and III. c) II, III, and IV. d) I and IV only. The velocity ratio is defined as the ratio of the distance moved by the effort to the distance moved by the load. 22 / 40 Category: JAMB Physics 2021 22. Relative density of a stone weighing $w_1$ in air and $w_2$ in water: a) $\frac{w_1}{w_2}$. b) $\frac{w_2}{w_1}$. c) $\frac{w_1 – w_2}{w_1}$. d) $\frac{w_1}{w_1 – w_2}$. Relative density is calculated using the formula $\frac{w_1}{w_1 – w_2}$. 23 / 40 Category: JAMB Physics 2021 23. Thickness of water when pin displacement viewed above is 3 cm: a) 4 cm. b) 3 cm. c) 5 cm. d) 2 cm. The formula for displacement helps find the actual thickness $h$. Solve for $h = 4$ cm. 24 / 40 Category: JAMB Physics 2021 24. Voltmeter reading when the circuit key is closed: a) Electromotive force. b) Terminal voltage. c) No reading. d) Short-circuit voltage. The voltmeter measures terminal voltage when current flows in the circuit. 25 / 40 Category: JAMB Physics 2021 25. Minimum distance for an echo when sound speed in air is 340 m/s: a) 160 m b) 150 m c) 180 m d) 170 m For an echo, minimum distance $d = \frac{vt}{2}$ gives $d = 170$ m. 26 / 40 Category: JAMB Physics 2021 26. Isotope decay producing $^{111}_{48}Y$: a) Beta emission b) Alpha emission c) Gamma decay d) Photon emission The correct decay process yields the isotope $^{111}_{48}Y$ 27 / 40 Category: JAMB Physics 2021 27. Definition of temperature -273°C: a) Boiling point b) Melting point c) Sublimation point d) Absolute zero of temperature This temperature is known as the absolute zero of temperature. 28 / 40 Category: JAMB Physics 2021 28. Moment of force 40 N about the point O: a) 60 Nm b) 80 Nm c) 120 Nm d) 140 Nm The moment of force is calculated using Moment = F × d. Here, Moment = 40 × 3 = 120 Nm. 29 / 40 Category: JAMB Physics 2021 29. Magnetic element not determining Earth’s magnetic field: a) Magnetic declination b) Magnetic inclination c) Electric induction d) Horizontal component The Earth’s magnetic field is determined by magnetic inclination, declination, and horizontal component but not electric induction. 30 / 40 Category: JAMB Physics 2021 30. Equivalent capacitance of the given circuit: a) 2 F b) 4 F c) 3 F d) 1 F For capacitors in series, the equivalent capacitance is $\frac{1}{C_{\text{eq}}} = \frac{1}{C_1} + \frac{1}{C_2}$. Solve to get 2 F. 31 / 40 Category: JAMB Physics 2021 31. Electric intensity experienced by a 60 C charge under 12 N force: a) 2.0 N/C b) 3.0 N/C c) 1.5 N/C d) 0.2 N/C Electric field intensity is calculated as $E = \frac{F}{q}$. Here, $E = \frac{12}{60} = 0.2$ N/C. 32 / 40 Category: JAMB Physics 2021 32. Major carriers in a p-type semiconductor material: a) Holes b) Electrons c) Protons d) Neutrons Holes are the majority charge carriers in p-type semiconductors due to the doping material used. 33 / 40 Category: JAMB Physics 2021 33. Coefficient of superficial expansion of a material given its dimensions and temperature change: a) $2.2 \times 10^{-6}$ K$^{-1}$ b) $3.3 \times 10^{-6}$ K$^{-1}$ c) $4.0 \times 10^{-6}$ K$^{-1}$ d) $4.4 \times 10^{-6}$ K$^{-1}$ Using the formula for expansion, coefficient $= \frac{\Delta L}{L \Delta T}$, solve to get $4.4 \times 10^{-6}$ K$^{-1}$ 34 / 40 Category: JAMB Physics 2021 34. Process involved in the absorption of ink by blotting paper: a) Capillary action b) Diffusion c) Osmosis d) Absorption Capillary action allows the ink to rise through the porous structure of the blotting paper. 35 / 40 Category: JAMB Physics 2021 35. Substance with the largest heat capacity: a) 1 kg of copper b) 10 kJ of water c) 1 kg of iron d) 2 kJ of mercury The substance with the largest heat capacity absorbs the most heat for the smallest temperature change. 36 / 40 Category: JAMB Physics 2021 36. Resulting motion of a hunter’s spear at 45°: a) Zero range b) Short range c) Maximum range d) Unpredictable At 45°, the projectile achieves maximum range because this angle optimizes horizontal and vertical components of motion. 37 / 40 Category: JAMB Physics 2021 37. Component NOT part of a D.C. generator: a) Split rings b) Commutator c) Brushes d) Slip rings Slip rings are components of an A.C. generator, while split rings are used in a D.C. generator. 38 / 40 Category: JAMB Physics 2021 38. Thermometric property NOT indicated: a) Change in resistance b) Change in volume c) Change in mass d) Change in pressure Mass is not a thermometric property, as it doesn’t change with temperature like volume, resistance, or pressure. 39 / 40 Category: JAMB Physics 2021 39. Frequency of wave in ripple tank: 60 waves in 30 seconds: a) 2 Hz b) 4 Hz c) 1 Hz d) 3 Hz Frequency $f = \frac{\text{Number of waves}}{\text{Time}} = \frac{60}{30} = 2$ Hz. 40 / 40 Category: JAMB Physics 2021 40. Mass of copper deposited with 1.5 A current in 900 s: a) $3.0 \times 10^{-4}$ kg b) $4.0 \times 10^{-4}$ kg c) $5.0 \times 10^{-4}$ kg d) $4.5 \times 10^{-4}$ kg Mass deposited $m = zIt$, where $z = 3.3 \times 10^{-2}$, $I = 1.5$ A, $t = 900$ s. Calculate $m = 3.3 \times 10^{-2} \times 1.5 \times 900 = 4.5 \times 10^{-4}$ kg. Your score is The average score is 0% LinkedIn Facebook Twitter VKontakte 0% Restart quiz Anonymous feedback Send feedback
