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Home / Science / BECE Past Questions & Answers – 1993 (SCIENCE)

BECE Past Questions & Answers – 1993 (SCIENCE)



August 1993


1 hour [60 marks]

Answerthreequestionsonlyfrom this section.
Illustrate your answerswherever possible, with large, clear and fully labelled diagrams. Creditwill be given for clarity of expression and orderlypresentation ofmaterial.
All questions carry equal marks

1. (a) Defin ethefollowingterms and give one exampleof each:
(i) Element
(ii) Mixture
(iii) Compound

(b) Explain the followingterms: (i) Work
(ii) Energy

(c) Statethe units in which each of thefollowing are measured: (i) Power
(ii) Energy
(iii) Electric current
(iv) Temperature

(d) A bodyof mass 100 kgis placed atapoint2 m abovetheground. What is the potential energyof the bodywith referenceto the ground? [Takeg=10 ms-2]

(e) Statethree characteristicsof each of the following: (i) An insect pollinated flower
(ii) A wind pollinated flower

2. (a) (i) Explain the term balanced diet.

(ii) Name anytwoclasses offoodwhich should bepresent in abalanced diet. (iii) Giveone function ofeach class of food named in (a) (ii)above.

(b) An object is placed in front of apinhole camera asshown in thediagram below:

Draw inyouranswer book a raydiagram (not to scale)to show howthe imageis formed on the screen of thecamera.

(c) Statethe two laws of reflection oflight.

(d) (i) Describehow ions are formed from atoms.
(ii) Statetwo differences between aproton and anelectron.

3. (a) (i) Explain the term electromagnetism.
(ii) Given anail, insulated wire, key(orswitch) andabattery, show bymeansofa circuit diagram how the nail canbemagnetized.

Listthreesymptoms ofmalaria.

Statethreeways of keepingtheenvironment clean.

Write down thenames ofthe new substances formed when the followingcompounds react: (i) Ammonia and dilute hydrochloricacid;
(ii) Sodiumhydroxide and dilute hydrochloricacid; (iii) Calcium carbonate and dilute hydrochloricacid.

4. (a) (i) What is meant byasatellite?
(ii) Stateonedifferencebetween anatural andan artificial satellite.
(iii) Statetwo uses of artificial satellite.

(b) Givetwo differences between the massand weight of abody.

(c) Write the chemical formulae forthefollowingsubstances. (i) Calcium oxide;
(ii) Water;
(iii) Copper sulphate

(d) What will be the effect on the colour ofblue litmus paper when itis droppedin each of the followingsolutions? CLICK TO VIEW ANSWERS TO PART 2

August 1993




1. (a) (i) Element
A substancethat is madeup ofthe same kind of atoms
Anysubstancethat cannot be broken down into asimpleronebya chemical reaction

A physical combination of two ormoresubstances
A substance consistingof two or moresubstancesthat havebeen combinedphysically

A substance formed bythe chemical combination of elements in fixed proportions
A substance containingtwo ormore elements that are chemicallycombined

(b) Explanation
(i) Work
Work is donewhen an applied forcemoves an object in the direction oftheforce.
Thetransfer ofenergy, measuredas the product ofthe force applied to a bodyand the distancemoved bythat bodyin thedirection ofthe force
Work = f × d, where f = forceapplied
and d = distance moved in the directionoftheappliedforce

(ii) Energy
The ability/ capacitytodo work

(c) UNIT
(i) (ii) (iii) (iv) Power
Temperature – watt(W)
– joule (J)
– ampere(A)
-Kelvin (K) or degreeCelsius (°C) ordegreeFahrenheit(°F)

(d) Potential Energy = mass ×height × acceleration due to gravity
= 100 kg×2 m×10 ms–2
= 2000kgm2s–2 or 2000 N

(e) Characteristics
(i) An insect pollinatedflower
 Petals arebrightlycoloured
 Larger sizeofflowers
 Nectarpresent
 Attractivescent
 Relativelyfewer but larger pollengrains

(ii) a wind pollinatedflower
 Dull coloured petals
 Nectarabsent
 No orunattractivescent
 Relativelymorebut smallerpollen grains

2. (a) (i) Balanced diet
A diet that contains all the essential food nutrientsin their right proportions

Classes of food
Carbohydrates, proteins, fats and oils, vitaminsand minerals


FoodClass Function(s)

Carbohydrates  Provide energyto thebody
 Glucose helps thebrain cells to function properly
 Glucose help maintain tissueprotein
 Glucose help metabolizefats
 Glucose fuels thecentralnervous system

Proteins  Build the bodycells / tissues
 Repair worn out /damaged bodycells/tissues
 Help speed upcertainchemical reactions in the body
 Help provide energyto thebodyif carbohydrates and fats areinsufficient

Fats and oils  Protect the bodyfrom extreme cold or heat
 Serveas a storeofenergyfor thebody
 Help in buildingthe membranes that surround the bodycells

 Help thebodyto absorbcertain vitamins

Vitamins  Strengthens the body’s immune system
 Helps thebodyto fightagainstdiseases
 Facilitates themetabolicactivities in thebody

Minerals  Ensurehealthygrowth ofteeth and bones
 Help with enzymeaction
 Help with muscle contraction
 Help with nerve reaction
 Help with blood clotting

(b) Diagramto showpinhole camera image


(c) Laws ofreflection oflight
 The angle ofincidenceis equal to the angle ofreflection

 Theincident ray, the reflected rayand the normal,at thepointof incidence,alllie in thesameplane

(d) (i) Howions areformed fromatoms
Atoms become chargedwhen theylose orgain electrons in order to bemorestable or attain a completelyfilledoutershell. When atoms gainelectrons, theybecome negatively charged ions, knownas anions; when theyloseelectrons, theybecomepositivelycharged ions, known as cations


positivelycharged negativelycharged

located in the nucleus ofan atom located outsidethe nucleus, on the
shells of an atom
relativelyheavy relativelyverylight

3. (a) (i) Electromagnetism
Magnetism produced byan electric current
Theprocess of makingamagnet usinganelectriccurrent

Diagramshowing hownailcan bemagnetized

(b) Symptoms ofmalaria
 fever
 bodypains
 feelingcold or hot
 headache
 nausea
 lack of appetite [anythree]

(c) Ways ofkeeping the environmentclean
 Clearing chokedgutters
 Clearing weedyareas
 Buryingemptycans
 Covering rubbish bins
 Sweepingdirtyareas
 Scrubbingtoilets and bathrooms

(D) NewSubstanceFormed
(i) Ammonia (NH3) and dilutehydrochloricacid(HCl);
NEW SUBSTANCE: Ammonium chloride (NH4Cl)

(ii) Sodiumhydroxide (NaOH) and dilute hydrochloric acid (HCl);
NEW SUBSTANCE: Sodiumchloride (NaCl)and water(H2O)

Calcium carbonate (CaCO3) and dilute hydrochloric acid (HCl).
NEW SUBSTANCE:Calcium chloride (CaCl2), Carbondioxide (CO2) and water(H2O)

A satellite is anyheavenlybodythat orbits (revolves around)alarger one.


Natural Satellite Artificial Satellite
Created byGod(ornature) Manufactured byman
Has no mechanical orelectrical
devices Has man-mademechanical or
electrical devices

(iii) Uses ofartificial satellites
 Weatherstudies and forecasting
 Telecommunication
 SendingandreceivingTV signals
 Takingphotographs fromspace for various purposes
 Internet networking
 Global PositioningSystem (GPS)-aworldwide navigation system


the amountof matter asubstance
contains the force exerted on abodyasa
remains constant (unchanging)
regardless of location varies with location
(dependingongravitational force acting at that point)
Units =kilogram (kg) Units =newton (N)

(i) Calciumoxide; CaO
(ii) (iii) Water;
Coppersulphate H2O CuSO4

(d) EFFECT ON BLUE LITMUS PAPER(i) Sodiumhydroxidesolution;- Remains blue

(iii) Breadat theduodenum
Enzymes in thepancreaticjuice, from the pancreas, break down thebread(sugars and starches) into simple sugars.

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