WAEC Physics 1988 Past Questions

Practice each question, then open it to see the full details.

Which of the units of the following physical quantities are derived? I. Area II. Thrust III. Pressure IV. Mass

A.I, II, III & IV
B.I, II, III only
C.I, II, IV only
D.I, & III only
E.I & IV only

(a) Explain with the aid of a diagram what is meant by the moment of a force about a point.

(b) State the conditions of equilibrium for a number of coplanar parallel forces.

A metre rule is found to balance at the 48cm mark. When a body of mass 60g is suspended at the 6cm mark, the balance point is found to be at the 30cm mark. Calculate:

(i) the mass of the metre rule; (ii) the distance of the balance point from the zero end, if the body were moved to the 13cm mark.

(c) Show that the efficiency E, the force ratio M.A and the velocity ratio V.R of a machine are related by the equation \(E = \frac{M.A}{V.R} \times 100%\)

The efficiency of a machine is 80%. Determine the work done by a person using this machine to raise a load of 200kg through a vertical distance of 3.0m.

[Take g = 10ms\(^{-2}\)]

The slope of a striaght line displacement time graph indicates the

A.Distance travelled
B.Uniform velocity
C.Uniform acceleration
D.Instantaneous acceleration
E.Uniform speed

(a) Draw a labelled diagram of a vacuum flask. Explain how its construction minimizes heat exchange with the surroundings.

(b) State Boyle's law. A thread of mercury of length 15cm is used to trap some air in a capillary tube with uniform cross- sectional area and closed at one end with the tube vertical and the open end uppermost, the length of the trapped air column is 20cm. Calculate the length of the air column when the tube is held:

(i) Horizontally ; (ii) vertically with the open end underneath. [Atmospheric pressure = 76cm Hg]

(c) Explain why it is not advisable to sterilize a clinical thermometer in boiling water at normal atmospheric pressure.

A man will exact the greatest pressure on a bench when he

A.lies flat on his back
B.lies flat on his belly
C.stand on both feet
D.stand on one foot only
E.stand on toes of one foot

(a) Explain with the aid of a diagram how a converging lens could be used to : (i) ignite a piece of carbon paper ; (ii) produce an enlarged picture on a screen ; (iii) correct an eye defect.

(b) What is a mechanical wave? Describe with the aid of a diagram, an experiment to show that sound needs a material medium for transmission.

State 3 characteristics of sound and mention the factor on which each depends.

When three coplanar and non-parallel forces are in equilibrium,
I. they can be represented in magnitude and direction by the three sides of a triangle taken in order.
II. their lines of action meet at a point.
III. the magnitude of anyone equals the magnitude of the resultant of the other two.
IV. any one force is the equilibrant of the other two.

Which of the following statements above are correct?

A.I & II only
B.II & III only
C.II, III & IV only
D.I, II, III & IV
E.I, III & IV only

(a) Explain what is meant by: (i) electric field intensity ; (ii) electric lines of force.

(b) Two similar but opposite point charges -q and +q each of magnitude \(5 \times 10^{-8} C\) are seperated by a distance of 8.0cm in vacuum as shown in the diagram below.

Calculate the magnitude and direction of the resultant electric field intensity E at the point P. Draw the lines of force due to this system of charges. [Take \(\frac{1}{4 \pi \varepsilon _{0}}\)]

(c) Calculate the following in the series circuit shown above: (i) reactance of the capacitor ; (ii) impedance of the circuit ; (iii) current through the circuit ; (iv) voltage across the capacitor ; (v) average power used in the circuit.

Sub-part image

Sub-part image

A ball of mass 0.5kg moving at 10ms^-1 collides with another ball of equal mass at rest. If the two balls move off together after the impact, calculate their common velocity.

A.0.2ms^-1
B.0.5ms^-1
C.5.0ms^-1
D.10.0ms^-1
E.20.0ms^-1

A body is projected into space with an initial velocity V₀ at an angle, θ to the horizontal. Which of the following statements is/are correct about its motion?
I. The total time of flight is (V₀ Cosθ)/g.
II. The maximum height is (V₀ Sin 2θ)/2g.
III. The range is (V₀² Cos²θ)/g.

A.I & II only
B.I & III only
C.II & III only
D.II only
E.III only

A catapult is used to project a stone. Which of the following energy conversions takes place as the stone is released?

A.The kinetic energy of the stone is converted into gravitational potential energy
B.The gravitational potential energy of the catapult is converted into kinetic energy of the stone
C.The gravitational potential energy is converted into elastic potential energy
D.The elastic potential energy of the catapult is converted into gravitational potential energy of the stone
E.None of the above

A ball is thrown vertically upwards from the ground with an initial velocity of 50ms^-1. What is the total time spent by the ball in the air? (g = 10ms^-2)

A.2.5s
B.5.0s
C.10.0s
D.15.0s
E.20.0s

Which of the following correctly gives the relationship between linear speed V and angular speed ω of a body moving uniformly in a circle of radius r?

A.V = ωr
B.V = ω²r
C.V = ωr²
D.V² = ωr
E.V = ω/r

The motion of a body is simple harmonic if the

A.Acceleration is always directed towards a fixed point
B.path of motion is a striaght line
C.Acceleration is directed towards a fixed point and proportional to its distance from the point
D.Acceleration is proportional to the square of the distance from a fixed point
E.Acceleration is constant and directed towards a fixed point

Which of the following statements about the gaseous state of matter is not correct? The molecules of a substance is in gaseous state

A.are in constant state of motion
B.have different speed
C.have a temperature which is an average measure of the kinetic energy
D.have no intermolecular attractive force
E.have a pressure which is determined by the number of molecules present

Which of the following cannot be used to measure the temperature of a substance?

A.variation of pressure with temperature
B.expansivity of a liquid
C.change in resistance of a conductor
D.thermometric effect
E.change in color with temperature

The clinical thermometer is characterized by having a

A.wide range of temperature
B.wide bore
C.long stem
D.constriction
E.narrow bore

A given mass of gas has a pressure of 80Nm^-2 at a temperature of 47^oC. If the temperature is reduced to 27^oC with the volume remaining constant, the new pressure is

A.46.0 Nm^-2
B.75.0 Nm^-2
C.80.0 Nm^-2
D.85.3 Nm^-2
E.139.4 Nm^-2

Which of the following is a reason why a concrete floor feels colder to the bare feet than a mat on the same floor during the rainy season?

A.A mat if s better conductor of heat than the feet
B.Mat losses heat to the bare feet at a faster rate than concrete floor
C.Mat losses heat to the bare feet while the concrete floor extracts heat from them
D.Concrete floor is a better conductor of heat than the mat
E.Mat is a better conductor of heat than the floor

In which of the following is the expansion of solids a disadvantage?

A.the fitting of wheels in rims
B.fire alarms
C.the thermostat
D.the bimatellic thermometer
E.the balance wheel of a watch

Which of the following best explains a person suffers more severe burns when his skin is exposed to steam than when boiling water is poured onto his skin?

A.steam is at a higher temperature than boiling water
B.steam posses greater heat energy per unit-mass than boiling water
C.steam spreads more easily over a wider area of the skin than boiling water
D.steam panetrates more easily over a wider area of the skin than boiling water
E.the specific latent heat of vaporization is released in changing from boiling water to steam

Which of the following statements about radiant heat is/are not correct?
I. radiant heat cannot travel through a vacuum
II. rough surfaces emit radiant heat more than polished surfaces
III. Dark surfaces absorb radiant heat more than bright surfaces

A.I only
B.II only
C.III only
D.I & II only
E.II & III only

0.5kg of water at 10^oC is completely converted to ice by extracting 188000J of heat from it. If the specific heat capacity of water is 4200J kg^-1C^-1, calculate the specific latent heat of fusion of ice.

A.9.0 KJ kg^-1
B.84.0 KJ kg^-1
C.168.0 KJ kg^-1
D.334.0 KJ kg^-1
E.336.0 KJ kg^-1

The temperature at which the water vapour present in the air is just sufficient to saturate it is called the

A.ice point
B.boiling point
C.steam point
D.dew point
E.saturation point

Which of the following instrument may be used to measure the relative humidity?

A.Hydrometer
B.Barometer
C.Manometer
D.Hypsometer
E.Hygrometer

Which of the following will affect the saturation vapour pressure of a liquid?

A.Temperature of the liquid
B.Humidity of air
C.Volume of vapour
D.Volume of the liquid
E.mass of the liquid

Which of the following statements is/are not correct about image formed by a plane mirror?
I. The magnification produced is 1
II. The image distance is same as the object distance
III. The image is real
IV. The image is laterally inverted

A.I only
B.II only
C.III only
D.I & II only
E.II & IV only

A transparent rectangular block 5.0cm thick is placed on a black dot. The dot when viewed from above is seem 3.0cm from the top of the block calculate the refractive index of the material of the block.

A.2/5
B.3/5
C.3/2
D.5/3
E.5/2

The velocities of light in air and glass are 3.0 x108ms-1 respectively. Calculate the sine of the angle of incidence that will produce an angle of refraction of 30 for a ray of light incident on glass.

A.1.2
B.1.0
C.0.8
D.0.6
E.0.3

An object is placed 36cm from a converging lens of focal length 24cm.If a real image which is 4cm high is formed, Calculate the height of the object.

A.2.0cm
B.4.0cm
C.6.0cm
D.8.0cm
E.10.0cm

The ability of the eye to focus objects at different distances is called

A.power
B.accommodation
C.normal vision
D.persistence of vision
E.long sight

The change of the direction of a wave-front because of a change in the velocity of the wave in another medium is called

A.refraction
B.reflection
C.diffraction
D.interference
E.dispersion

A source of sounds produces waves in air of wavelength1.65m. If the speed of sound in air is 330ms-1 the period of vibration in seconds is

A.200
B.2.0
C.0.5
D.0.02
E.0.005

Which of the following statement s is/are not correct about a standing wave? I. It is formed by the superimposition of two progressive waves traveling in the same direction II. All points on the wave are vibrating with maximum displacement III. It is formed by the superimposition of two progressive waves of different amplitudes traveling in opposite directions

A.I only
B.II only
C.I and II only
D.II and III only
E.I,II and III

A boy standing a distance from the foot of a tall cliff claps his hands and hears an echo 0.5s later. If the speed of sound is 340ms1, how far is he from the cliff?

A.17m
B.34m
C.85m
D.170m
E.680m

A sounding tuning fork is brought near the end of a pipe containing an air column and the loudness of the sound increases. This effect is due to

A.diffraction
B.an echo
C.resonance
D.interference
E.reverberation

If the leaves a positively charged electroscope collapse completely as an object is brought near the cap of the electroscope, the objects possesses

A.an equal amount of positive charge
B.less amount of negative charge
C.no charge
D.a positive charge
E.an equal amount of negative charge

A transformer with 55500 turns in its primary is used between a 240V a. c supply and a 120V kettle. Calculate the number of turns in the secondary

A.11000
B.2750
C.460
D.232
E.10

Local action is normally prevented from taking place in a simple electric cell by

A.introducing an oxidising agent into the acid
B.not drawing current continuously for long periods
C.amalgamating the surface of the zinc plate
D.using a porous pot to isolate the zinc plate from the acid
E.using dilute sulphuric acid

A cell can supply current of 0.8A and 0.4A through a 2Ω and a 3Ω resistors respectively. Calculate the internal resistance of the cell.

A.0.2Ω
B.0.4Ω
C.-1.0Ω
D.3.0Ω
E.9.0Ω

A battery of emf 24V and internal resistance 4Ω is connected to a resistor of 32Ω. What is the terminal p.d of the battery?

A.24.0V
B.21.3V
C.16.0V
D.2.7V
E.2.0V

Two parallel conductors carry equal currents in the same direction. Which of the following statement is not a correct observation?

A.Each of teh conductors will experience a force
B.Each of the conductors can move
C.The forces on the conductors will be equal
D.There are concentric lines of force around each conductor
E.The two conductors will repel each other

It takes 4 minutes to boil a quantity of water electrically. How long will it take to boil same quantity of water using the same heating coil but with the current doubled? (neglecting any external heat loss).

A.64 minutes
B.32 minutes
C.8 minutes
D.2 minutes
E.1 minute

A lamp is marked 220V 60 W. Calculate the energy it would consume when connected to a 220V source for 1 hour.

A.216000J
B.13200J
C.3600J
D.864J
E.220J

What is the effect of using split-rings in a simple d.c motor?

A.The direction of rotation of the coil is reversed
B.The current in the coil flows in the same direction
C.The current in the coil becomes alternating
D.The direction of the force on the coil is reversed
E.The contact with the voltage is cut-off

Which of the following statement is not correct about loaded spiral spring?

A.The extension is proportional to the load applied, provided the elastic limite is not exceeded
B.If the elsatic limit is not exceeded, the contraction is proportional to the load removed.
C.Up to the yield limit, extension is no longer proportional to the applied load.
D.Beyond the elsatic limit, extension is no longer proportional to the applied load.
E.If the string regains its shape or form after deformation, it is said to be elastic.

Calculate the resistivity of a wire of length 2m and cross-sectional area 0.004cm² if the resistance is 3.0 Ω.

A.0.0000267Ωcm
B.0.006Ωcm
C.0.26700Ωcm
D.0.27500Ωcm
E.0.060000Ωcm

Which of the following particles of ray has the highest penetrating power?

A.Beta particles
B.Alpha particles
C.Gamma particles
D.Electrons
E.Neutrons

When sugar at the bottom of a glass of water gradually dissolves, the water level does not change applicably. Which of the following statements best describe this?

A.Water is suitable solvent for sugar
B.The sugar and the water have become single solution
C.The volume of water molecule does not change when sugar dissolves.
D.Sugar molecule is small than that of water
E.Water molecules are separated by large spaces between them

Which of the following explains the concave meniscus of water in a glass tube?

A.The adhesion between water and glas is greater than the cohesion between water molecules
B.The cohesion between water molecule is greater than the adhesion between glass and water
C.The molecules of water in the glass are moving faster than the molecules in the other parts
D.The molecules of water at the water-air boundary are often attracted to the center of the tube
E.The weight of the water pulls the central part of the surface down