Sample WAEC-style Practice Questions (Original Content)
WAEC Style
Question 1
Which of the following is a scalar quantity?
A. Displacement
B. Acceleration
C. Work
D. Force
Answer: C. Work
Explanation: Work has magnitude but no specific direction. Displacement, acceleration, and force are all vector quantities.
Question 2
A spring of natural length 10cm is stretched to 15cm by a force of 20N. Calculate the spring constant.
A. 400 N/m
B. 4 N/m
C. 200 N/m
D. 100 N/m
Answer: A. 400 N/m
Explanation: Extension e = 15cm - 10cm = 5cm = 0.05m. Using F = ke, k = F / e = 20 / 0.05 = 400 N/m.
Question 3
Pressure in a liquid depends on which of the following factors?
A. Area of the surface
B. Depth and density of the liquid
C. Shape of the container
D. Volume of the liquid
Answer: B. Depth and density of the liquid
Explanation: Pressure P = h * rho * g, where h is depth and rho is density.
Question 4
Which instrument is used to measure atmospheric pressure?
A. Hydrometer
B. Hygrometer
C. Barometer
D. Manometer
Answer: C. Barometer
Explanation: A barometer measures air pressure. A manometer measures gas pressure in a container.
Question 5
According to Archimedes' principle, upthrust is equal to the:
A. Mass of the fluid displaced
B. Weight of the fluid displaced
C. Density of the object
D. Volume of the object
Answer: B. Weight of the fluid displaced
Explanation: The upward force (upthrust) on a body immersed in a fluid is equal to the weight of the fluid that the body moves out of the way.
Question 6
The force required to keep a body moving in a circular path is called:
A. Centrifugal force
B. Gravitational force
C. Centripetal force
D. Frictional force
Answer: C. Centripetal force
Explanation: Centripetal force acts towards the center of the circle to maintain circular motion.
Question 7
A uniform meter rule is balanced at the 50cm mark. If a 2N weight is hung at the 10cm mark, where must a 4N weight be hung to balance the rule?
A. 60 cm mark
B. 70 cm mark
C. 80 cm mark
D. 90 cm mark
Answer: B. 70 cm mark
Explanation: Clockwise moment = Anticlockwise moment. 4 * x = 2 * (50-10). 4x = 80. x = 20cm from the pivot. 50 + 20 = 70cm mark.
Question 8
"To every action, there is an equal and opposite reaction." This is:
A. Newton's First Law
B. Newton's Second Law
C. Newton's Third Law
D. Hooke's Law
Answer: C. Newton's Third Law
Explanation: This law describes the interaction between two bodies.
Question 9
The period of a simple pendulum depends on its:
A. Mass of the bob
B. Amplitude of swing
C. Length of the string
D. Density of the bob
Answer: C. Length of the string
Explanation: Period T = 2 * pi * sqrt(L / g). It is independent of mass and amplitude (for small angles).
Question 10
A boy of mass 50kg runs up a flight of stairs 4m high in 5 seconds. Calculate his power output. (g = 10 m/s2)
A. 40 W
B. 400 W
C. 200 W
D. 1000 W
Answer: B. 400 W
Explanation: Work = mgh = 50 * 10 * 4 = 2000 J. Power = Work / Time = 2000 / 5 = 400 Watts.
Question 11
Calculate the heat needed to raise the temperature of 2kg of water from 20 to 30 degrees Celsius. (Specific heat capacity of water = 4200 J/kg/K)
A. 84,000 J
B. 42,000 J
C. 10,000 J
D. 21,000 J
Answer: A. 84,000 J
Explanation: Q = mc * delta theta. Q = 2 * 4200 * (30 - 20) = 2 * 4200 * 10 = 84,000 J.
Question 12
The law which relates the volume and absolute temperature of a gas at constant pressure is:
A. Boyle's Law
B. Charles's Law
C. Dalton's Law
D. Pressure Law
Answer: B. Charles's Law
Explanation: V1 / T1 = V2 / T2 at constant pressure.
Question 13
Which instrument is used to measure relative humidity?
A. Hydrometer
B. Barometer
C. Hygrometer
D. Pyrometer
Answer: C. Hygrometer
Explanation: A hygrometer (or psychrometer) measures the amount of water vapor in the air.
Question 14
Evaporation differs from boiling because evaporation:
A. Occurs throughout the liquid
B. Occurs only at a specific temperature
C. Causes a cooling effect
D. Is a fast process
Answer: C. Causes a cooling effect
Explanation: Evaporation happens at the surface at any temperature and results in the removal of heat from the liquid.
Question 15
Water shows anomalous expansion between:
A. 0 and 100 degrees C
B. -4 and 0 degrees C
C. 0 and 4 degrees C
D. 4 and 10 degrees C
Answer: C. 0 and 4 degrees C
Explanation: Water contracts when heated from 0 to 4 degrees Celsius and expands when cooled in this range.
Question 16
Total Internal Reflection occurs when light travels from a:
A. Less dense to a more dense medium
B. More dense to a less dense medium
C. Vacuum to air
D. Water to glass
Answer: B. More dense to a less dense medium
Explanation: It also requires the angle of incidence to be greater than the critical angle.
Question 17
The power of a lens is 2.0 Dioptres. What is its focal length?
A. 2.0 m
B. 1.0 m
C. 0.5 m
D. 0.2 m
Answer: C. 0.5 m
Explanation: Power P = 1 / f (in meters). f = 1 / 2 = 0.5 m.
Question 18
Which of the following is a primary pigment color?
A. Red
B. Green
C. Yellow
D. White
Answer: C. Yellow
Explanation: Primary pigment (subtractive) colors are Red, Blue, and Yellow. Primary light (additive) colors are Red, Green, and Blue.
Question 19
A wave has a speed of 340 m/s and a frequency of 170 Hz. Calculate its wavelength.
A. 0.5 m
B. 2.0 m
C. 1.0 m
D. 57800 m
Answer: B. 2.0 m
Explanation: v = f * lambda. lambda = v / f = 340 / 170 = 2.0 m.
Question 20
When two systems vibrate at the same natural frequency, the phenomenon is called:
A. Reverberation
B. Beats
C. Resonance
D. Interference
Answer: C. Resonance
Explanation: Resonance results in a large amplitude of vibration.
Question 21
The change in the observed frequency of a wave due to relative motion is the:
A. Compton effect
B. Photoelectric effect
C. Doppler effect
D. Tyndall effect
Answer: C. Doppler effect
Explanation: This occurs with both sound and light waves.
Question 22
The unit of electric field intensity is:
A. Volt-meter
B. Newton per Coulomb
C. Coulomb per Newton
D. Ampere per meter
Answer: B. Newton per Coulomb
Explanation: E = F / q, hence N/C. It is also measured in V/m.
Question 23
Two resistors of 4 ohms and 6 ohms are connected in series. What is the total resistance?
A. 2.4 ohms
B. 10 ohms
C. 24 ohms
D. 2 ohms
Answer: B. 10 ohms
Explanation: In series, Reff = R1 + R2 = 4 + 6 = 10 ohms.
Question 24
A current of 0.5A flows through a resistor of 10 ohms. Calculate the potential difference.
A. 5 V
B. 20 V
C. 2.5 V
D. 0.05 V
Answer: A. 5 V
Explanation: Using V = I * R. V = 0.5 * 10 = 5 Volts.
Question 25
According to Faraday's first law of electrolysis, the mass of substance deposited is proportional to:
A. Molar mass
B. Current squared
C. Quantity of electricity (Q)
D. Resistance
Answer: C. Quantity of electricity (Q)
Explanation: M = Z * Q = Z * I * t.
Question 26
Which of the following is a "soft" magnetic material?
A. Steel
B. Iron
C. Alnico
D. Cobalt
Answer: B. Iron
Explanation: Soft iron is easily magnetized and demagnetized, making it suitable for electromagnets.
Question 27
Lenz's law is a consequence of the law of conservation of:
A. Charge
B. Mass
C. Momentum
D. Energy
Answer: D. Energy
Explanation: It states that the induced current flows in a direction that opposes the change producing it.
Question 28
The process of converting alternating current to direct current is:
A. Induction
B. Amplification
C. Rectification
D. Capacitance
Answer: C. Rectification
Explanation: Diodes are used as rectifiers to allow current to flow in one direction only.
Question 29
The emission of electrons from a heated metal filament is called:
A. Photoelectric effect
B. Thermionic emission
C. Field emission
D. Secondary emission
Answer: B. Thermionic emission
Explanation: Heat energy provides the electrons with enough energy to escape the surface of the metal.
Question 30
A radioactive source has a half-life of 2 hours. If its initial mass is 100g, how much is left after 6 hours?
A. 50 g
B. 25 g
C. 12.5 g
D. 6.25 g
Answer: C. 12.5 g
Explanation: 6 hours = 3 half-lives. 100g -> 50g -> 25g -> 12.5g.
Question 31
Which of the following radiations has the highest penetrating power?
A. Alpha particles
B. Beta particles
C. Gamma rays
D. X-rays
Answer: C. Gamma rays
Explanation: Gamma rays are high-energy photons with no mass or charge, allowing them to penetrate deep into matter.
Question 32
The weight of an object is 600N on Earth. What is its weight on the Moon? (g moon = 1/6 g earth)
A. 600 N
B. 100 N
C. 3600 N
D. 0 N
Answer: B. 100 N
Explanation: Weight W = m * g. Since g is 1/6th, weight is 600 / 6 = 100N.
Question 33
The skin of a liquid acts like an elastic membrane due to:
A. Viscosity
B. Adhesion
C. Surface tension
D. Friction
Answer: C. Surface tension
Explanation: This is caused by cohesive forces between liquid molecules.
Question 34
The internal friction between layers of a liquid is:
A. Surface tension
B. Viscosity
C. Capillarity
D. Upthrust
Answer: B. Viscosity
Explanation: High viscosity means the fluid is "thick" and flows slowly (like honey).
Question 35
Which planet is the smallest in the solar system?
A. Mars
B. Venus
C. Mercury
D. Neptune
Answer: C. Mercury
Explanation: Mercury is the innermost and smallest planet.
Question 36
A projectile is fired with an initial velocity of 20 m/s at an angle of 30 degrees. Calculate the time of flight. (g = 10 m/s2)
A. 1 s
B. 2 s
C. 4 s
D. 1.73 s
Answer: B. 2 s
Explanation: T = (2 * u * sin theta) / g = (2 * 20 * sin 30) / 10 = (40 * 0.5) / 10 = 2 seconds.
Question 37
Which of the following is an example of simple harmonic motion?
A. A car moving on a highway
B. A ball bouncing on the floor
C. The motion of a simple pendulum
D. A bird flying
Answer: C. The motion of a simple pendulum
Explanation: SHM is a repetitive back-and-forth motion through an equilibrium position.
Question 38
The best material for making a cooking pot is one with:
A. High specific heat and low conductivity
B. Low specific heat and high conductivity
C. High specific heat and high conductivity
D. Low specific heat and low conductivity
Answer: B. Low specific heat and high conductivity
Explanation: High conductivity ensures fast heat transfer, and low specific heat means it heats up quickly.
Question 39
The type of radiation that has the longest wavelength in the electromagnetic spectrum is:
A. Gamma rays
B. Radio waves
C. Ultraviolet rays
D. Infrared rays
Answer: B. Radio waves
Explanation: Radio waves have the lowest frequency and the longest wavelength.
Question 40
A converging mirror produces a real image when the object is placed:
A. Between the pole and focus
B. At the focus
C. Beyond the focus
D. At infinity only
Answer: C. Beyond the focus
Explanation: If placed between the pole and focus, the image is virtual.
Question 41
The speed of sound in air increases with an increase in:
A. Pressure
B. Amplitude
C. Temperature
D. Frequency
Answer: C. Temperature
Explanation: Sound speed is independent of pressure but depends on the square root of the absolute temperature.
Question 42
A man stands 170m away from a wall and claps his hands. If the speed of sound is 340 m/s, how long until he hears the echo?
A. 0.5 s
B. 1.0 s
C. 2.0 s
D. 1.5 s
Answer: B. 1.0 s
Explanation: Distance d = (v * t) / 2. 170 = (340 * t) / 2. 170 = 170 * t. t = 1.0 second.
Question 43
A fuse is a safety device connected in:
A. Parallel with the live wire
B. Series with the live wire
C. Series with the neutral wire
D. Parallel with the earth wire
Answer: B. Series with the live wire
Explanation: This ensures that if current is too high, the fuse melts and breaks the circuit.
Question 44
A capacitor of 10 microFarads is charged to a potential of 100V. Calculate the energy stored.
A. 0.05 J
B. 0.1 J
C. 1.0 J
D. 0.5 J
Answer: A. 0.05 J
Explanation: Energy E = 0.5 * C * V2 = 0.5 * (10 * 10 to the power of -6) * 100 * 100 = 0.05 Joules.
Question 45
The direction of a magnetic field around a straight current-carrying wire is determined by:
A. Fleming's Left Hand Rule
B. Fleming's Right Hand Rule
C. Right-Hand Grip Rule
D. Lenz's Law
Answer: C. Right-Hand Grip Rule
Explanation: Thumb points in the direction of current, and fingers curl in the direction of the magnetic field.
Question 46
In Einstein's photoelectric equation (hf = W + K), "W" represents the:
A. Wavelength of light
B. Work done
C. Work function
D. Wave speed
Answer: C. Work function
Explanation: Work function is the minimum energy needed for an electron to escape the metal surface.
Question 47
The sun produces its energy through the process of:
A. Nuclear fission
B. Nuclear fusion
C. Chemical combustion
D. Radioactivity
Answer: B. Nuclear fusion
Explanation: Hydrogen nuclei fuse together to form Helium, releasing massive amounts of energy.
Question 48
A satellite that remains over the same spot on the Earth's surface is a:
A. Polar satellite
B. Geostationary satellite
C. Astronomical satellite
D. Low Earth orbit satellite
Answer: B. Geostationary satellite
Explanation: Its period of rotation matches the Earth's period (24 hours).
Question 49
Which of the following is NOT a fundamental quantity?
A. Length
B. Luminous Intensity
C. Velocity
D. Time
Answer: C. Velocity
Explanation: Velocity is a derived quantity (Displacement / Time).
Question 50
The dimension of Force is given by:
A. [MLT-1]
B. [MLT-2]
C. [ML2T-2]
D. [ML-3]
Answer: B. [MLT-2]
Explanation: Force = Mass * Acceleration = M * (LT to the power of -2).