Zambia School Certificate / GCE — Science (5124)

Which of the following is an SI base quantity with its correct base unit?

• AMass — kilogram
• BForce — newton
• CSpeed — metre per second
• DEnergy — joule

Density is defined as

• Amass divided by volume
• Bweight divided by volume
• Cmass multiplied by volume
• Dvolume divided by mass

A copper block has mass 216 g and volume 24 cm³. What is its density?

• A5.2 g/cm³
• B9.0 g/cm³
• C8.0 g/cm³
• D0.11 g/cm³

Which pair is a scalar quantity followed by a vector quantity?

• ASpeed, velocity
• BVelocity, speed
• CForce, mass
• DDisplacement, distance

A bicycle increases its velocity from 4 m/s to 12 m/s in 8 s. What is its average acceleration?

• A0.5 m/s²
• B1.0 m/s²
• C1.5 m/s²
• D2.0 m/s²

A learner has a mass of 50 kg. Taking g = 10 N/kg, what is the learner’s weight on Earth?

• A5 N
• B50 N
• C500 N
• D5000 N

Two forces of 12 N and 8 N act on a body along the same straight line but in opposite directions. What is the magnitude of the resultant force?

• A4 N
• B8 N
• C12 N
• D20 N

A force of 20 N acts perpendicular to a door at a distance of 0.80 m from the hinges. What is the moment of the force about the hinges?

• A16 N m
• B20 N m
• C25 N m
• D0.04 N m

Work is done when a force

• Amoves its point of application in the direction of the force
• Bacts on a stationary object that does not move
• Cis balanced by an equal opposite force with no displacement
• Dacts at right angles to a displacement of zero distance

A crane does 2400 J of work in 12 s. What is its useful power output?

• A20 W
• B200 W
• C240 W
• D28800 W

A 2.0 kg trolley moves at 3.0 m/s. What is its kinetic energy?

• A3.0 J
• B6.0 J
• C9.0 J
• D18 J

A crowbar used to lift a crate is an example of

• Aa lever
• Ba pulley
• Can inclined plane
• Da screw jack

A machine has a velocity ratio of 5. A 20 N effort raises a 80 N load. What is the efficiency of the machine?

• A20%
• B25%
• C80%
• D100%

Pressure in a fluid is calculated as

• Aforce divided by area
• Bforce multiplied by area
• Cmass divided by volume
• Dweight multiplied by height

A box of weight 400 N rests on a floor on an area of 0.050 m². What pressure does it exert on the floor?

• A20 Pa
• B8000 Pa
• C20 000 Pa
• D800 000 Pa

A solid of density 0.80 g/cm³ is placed in water of density 1.0 g/cm³. What happens, and why?

• AIt floats, because its density is less than that of water
• BIt sinks, because its mass is less than that of water
• CIt floats, because its volume is greater than that of water
• DIt sinks, because its weight is greater than the upthrust on a fully submerged equal volu…

On a velocity–time graph, the area between the line and the time axis represents

• Adisplacement (distance travelled in a stated direction)
• Bacceleration
• Cinstantaneous speed only
• Dresultant force

When a learner rides a bicycle, chemical energy in food is converted mainly into

• Akinetic energy of the bicycle and rider, plus heat
• Bnuclear energy in the muscles
• Cgravitational potential energy only, even on level ground
• Dlight energy stored in the tyres

Heat is transferred through the metal of a cooking pot mainly by

• Aconduction
• Bconvection
• Cradiation only
• Devaporation

A convection current in a pan of water rises because the heated water

• Aexpands, becomes less dense and is pushed up by cooler, denser water
• Bcontracts, becomes denser and sinks
• Cturns into steam immediately throughout the pan
• Dstops conducting heat so the only transfer is radiation

Which surface is the best absorber of thermal radiation?

• ADull black
• BShiny silver
• CWhite polished
• DClear glass

A metal bridge is built with expansion gaps. The gaps are needed because when the temperature rises the metal

• Aexpands and would buckle if it had no room to lengthen
• Bcontracts and would snap if it were continuous
• Cchanges into a liquid at ordinary air temperatures
• Dbecomes a better electrical insulator

The frequency of a wave is the

• Anumber of complete waves passing a point each second
• Bdistance between two successive crests
• Cmaximum displacement from the rest position
• Dtime for one complete wave to pass a point

A sound wave of frequency 220 Hz travels in air at 330 m/s. What is its wavelength?

• A0.67 m
• B1.5 m
• C110 m
• D55000 m

Sound cannot travel through a vacuum because sound

• Aneeds a material medium whose particles can vibrate
• Bis a transverse electromagnetic wave
• Ctravels only through metals
• Dhas zero frequency in air

A learner stands 165 m from a high wall and hears an echo 1.0 s after clapping. What is the speed of sound in the air?

• A165 m/s
• B330 m/s
• C82.5 m/s
• D3300 m/s

A ray of light slows down as it passes from air into glass. The ray

• Abends towards the normal
• Bbends away from the normal
• Cis reflected with angle of reflection greater than the angle of incidence
• Dstops at the surface

An object is placed farther from a thin converging lens than the focal length but closer than twice the focal length. The image is

• Areal, inverted and magnified
• Breal, inverted and diminished
• Cvirtual, upright and diminished
• Dvirtual, upright and the same size

In the Science 5124 treatment of circuits, conventional current is taken as the flow of

• Apositive charge from the positive terminal to the negative terminal
• Belectrons from the positive terminal to the negative terminal
• Cprotons through the connecting wires
• Dneutrons from the battery into the bulb

An ammeter is connected

• Ain series with the component, because it has a very low resistance
• Bin parallel with the component, because it has a very high resistance
• Cin series with the component, because it has a very high resistance
• Din parallel with the cell only, never in the load circuit

A 6.0 V cell is connected across a 3.0 Ω resistor. What is the current in the resistor?

• A0.50 A
• B2.0 A
• C9.0 A
• D18 A

Two resistors of 4.0 Ω and 6.0 Ω are connected in series with a 20 V battery of negligible internal resistance. What is the current in the circuit?

• A2.0 A
• B3.3 A
• C5.0 A
• D8.0 A

Two 6.0 Ω resistors are connected in parallel. What is the combined resistance?

• A3.0 Ω
• B6.0 Ω
• C12 Ω
• D0.33 Ω

The heating effect of an electric current is used in

• Aan electric iron
• Ban electric bell
• Ca plotting compass
• Da step-up transformer

Which statement about bar magnets is correct?

• ALike poles repel and unlike poles attract
• BLike poles attract and unlike poles repel
• CBoth poles of a magnet attract both poles of another magnet
• DA north pole attracts another north pole

A current-carrying coil wound on a soft-iron core is used in an electric bell because the core

• Astores electric charge like a capacitor
• Bbecomes a temporary magnet that can be switched on and off
• Cbecomes a permanent magnet that stays magnetised when the current stops
• Dinsulates the coil so that no magnetic field is produced

An e.m.f. is induced in a coil when

• Athe temperature of the coil is constant and there is no field
• Bthe magnetic field through the coil is changing
• Ca steady current has flowed in a nearby circuit for a long time with no change
• Dthe coil is made of wood instead of copper

A transformer has 200 turns on the primary and 1000 turns on the secondary. The primary is connected to a 12 V a.c. supply. What is the secondary voltage if the transformer is ideal?

• A2.4 V
• B12 V
• C60 V
• D240 V

A plastic ruler rubbed with a dry cloth becomes negatively charged. This happens because

• Athe cloth creates new electrons on the ruler
• Belectrons move from the cloth onto the ruler
• Cprotons move from the ruler onto the cloth
• Delectrons move from the ruler onto the cloth

A radioactive source has a half-life of 2 hours. A sample gives a corrected count rate of 800 counts/min. What is the corrected count rate after 6 hours?

• A400 counts/min
• B100 counts/min
• C200 counts/min
• D267 counts/min

Which radiation is the most penetrating and is stopped only by thick lead or concrete?

• AAlpha particles
• BBeta particles
• CGamma rays
• DSlow protons from a battery

A charge of 30 C flows through a lamp in 10 s. What is the current in the lamp?

• A0.33 A
• B3.0 A
• C40 A
• D300 A

Matter is anything that

• Acannot change from one state to another
• Bhas mass and occupies space
• Ccan be seen with the naked eye
• Dis always a solid at room temperature

According to the kinetic theory, the particles of a gas

• Ado not move at all at room temperature
• Bmove rapidly and randomly with large spaces between them
• Cvibrate about fixed positions in a regular lattice
• Dare tightly packed and slide over one another only

A crystal of potassium permanganate is placed at the bottom of a beaker of still water. After some time the water is purple throughout. The main process is

• Afiltration
• Bdiffusion
• Cosmosis through a membrane
• Delectrolysis

Which method is best for obtaining pure water from a solution of copper(II) sulfate?

• AUse of a magnet
• BSimple distillation
• CFiltration
• DDecanting only

A liquid boils over a range of temperatures rather than at one sharp temperature. This suggests that the liquid is

• Aan insoluble solid
• Ba mixture
• Ca pure element
• Da pure compound

The smallest particle of an element that still has the chemical properties of that element is

• Aa mixture
• Ban atom
• Ca molecule of a compound
• Da proton alone