Question 1 (B1.1)
A scientist is studying a living organism. She observes that it has the ability to remove the waste products of metabolism.
What characteristic of living organisms is being observed?
A. excretion
B. nutrition
C. respiration
D. reproduction
▶️Answer/Explanation
Answer: A
Explanation: Excretion is the process by which organisms remove metabolic waste products from their bodies. This is one of the key characteristics of living organisms, distinguishing them from non-living things. Nutrition (B) involves taking in food, respiration (C) is the release of energy from food, and reproduction (D) is the production of offspring.
Question 2 (B3.2)
Pieces of potato (a plant) of the same size were placed in sucrose solutions of different concentrations. Their length was measured after two hours.
At which sucrose concentration were the pieces most flaccid?
▶️Answer/Explanation
Answer: D
Question 3 (B4.1)
A food contains reducing sugar, but no starch.
What colours will be obtained if samples of the food are tested with Benedict’s solution and with iodine solution?
| Benedict’s test | iodine test | |
|---|---|---|
| A | blue | blue-black |
| B | blue | brown |
| C | red-orange | blue-black |
| D | red-orange | brown |
▶️Answer/Explanation
Answer: D
Explanation: Benedict’s solution turns from blue to red-orange in the presence of reducing sugars. Iodine solution remains brown when no starch is present (it only turns blue-black if starch is present). Since the food contains reducing sugar but no starch, the correct combination is red-orange with Benedict’s and brown with iodine.
Question 4 (B5.1)
Which type of molecule is an enzyme?
A. carbohydrate
B. fat
C. protein
D. vitamin
▶️Answer/Explanation
Answer: C
Explanation: All enzymes are proteins that act as biological catalysts. While some vitamins may assist enzyme function as coenzymes, the enzymes themselves are always protein molecules with a specific active site that binds to substrates.
Question 5 (B6.2)
Which part of a leaf is involved in opening and closing the stomata during gas exchange?
A. chloroplast
B. guard cell
C. palisade mesophyll
D. phloem
▶️Answer/Explanation
Answer: B
Explanation: Guard cells are specialized cells that surround each stoma. They change shape (by taking in or losing water) to open or close the stomatal pore, regulating gas exchange and transpiration. Chloroplasts (A) are organelles for photosynthesis, palisade mesophyll (C) is the main photosynthetic tissue, and phloem (D) transports sugars.
Question 6 (B7.1)
Why is calcium needed in the diet?
A. to make carbohydrates
B. to make teeth
C. to make enzymes
D. to make protein
▶️Answer/Explanation
Answer: B
Explanation: Calcium is essential for the formation and maintenance of strong teeth and bones. It combines with phosphate to form calcium phosphate, which gives hardness to teeth and bones. While calcium has other roles (like nerve transmission), its primary dietary importance is for skeletal structures.
Question 7 (B9.3)
Which blood vessel carries deoxygenated blood and has a thick muscular wall?
A. aorta
B. pulmonary artery
C. pulmonary vein
D. vena cava
▶️Answer/Explanation
Answer: B
Explanation: The pulmonary artery is the only artery that carries deoxygenated blood (from heart to lungs) and has a thick muscular wall like other arteries. The aorta (A) carries oxygenated blood, pulmonary veins (C) carry oxygenated blood, and vena cava (D) carries deoxygenated blood but has thin walls like all veins.
Question 8 (B12.1)
Which row shows the products of anaerobic respiration in yeast cells?
| lactic acid | CO2 | alcohol | |
|---|---|---|---|
| A | ✓ | ✗ | ✗ |
| B | ✗ | ✓ | ✓ |
| C | ✗ | ✗ | ✓ |
| D | ✓ | ✓ | ✗ |
▶️Answer/Explanation
Answer: B
Explanation: Yeast cells perform alcoholic fermentation during anaerobic respiration, producing ethanol (alcohol) and carbon dioxide. Lactic acid is produced by animal cells during anaerobic respiration, not yeast. Therefore, the correct products are CO2 and alcohol, with no lactic acid.
Question 9 (B13.3)
What happens when the body temperature falls below normal?
A. Arterioles supplying the skin constrict.
B. Arterioles supplying the skin dilate.
C. Capillaries move towards the skin surface.
D. Capillaries move away from the skin surface.
▶️Answer/Explanation
Answer: A
Explanation: When body temperature drops, vasoconstriction occurs – arterioles supplying the skin constrict to reduce blood flow near the skin surface, minimizing heat loss. This is part of the body’s thermoregulatory response to conserve heat. Vasodilation (B) would occur if the body needed to lose heat.
Question 10 (B15.3)
The diagram shows a section through a pea flower.
Where does fertilisation occur?
▶️Answer/Explanation
Ans: C
Question 11 (B16)
The diagram shows the inheritance of a disease.
Which row is correct for the parents and the allele for the disease?
▶️Answer/Explanation
Answer: B
Explanation: The pedigree shows unaffected parents producing affected offspring, which indicates that both parents must be heterozygous carriers (Aa) and the disease allele is recessive. If it were dominant, at least one affected parent would be required to produce affected offspring.
Question 12 (B18)
Where does the principle source of energy for an ecosystem come from?
A. decay
B. the soil
C. the Sun
D. water
▶️Answer/Explanation
Answer: C
Explanation: The Sun is the primary source of energy for almost all ecosystems. Producers (plants) convert solar energy into chemical energy through photosynthesis, which then flows through the food chain.
Question 13 (B19)
Which line shows how the oxygen concentration of the water changes after excess fertilizer has entered a stream?
▶️Answer/Explanation
Answer: B
Explanation: Excess fertilizer causes algal blooms which initially decrease oxygen as algae respire at night. When algae die, decomposers further deplete oxygen. Eventually, as the ecosystem recovers, oxygen levels increase again.
Question 14 (C2)
Which statement about atoms and molecules is correct?
A. All molecules are gases at room temperature and pressure.
B. An atom is the smallest part of an element.
C. Atoms of the same element all have the same mass.
D. Molecules always contain atoms of more than one element.
▶️Answer/Explanation
Answer: B
Explanation: An atom is indeed the smallest particle of an element that retains its chemical properties. Option A is incorrect because molecules can be solids, liquids or gases. C is wrong due to isotopes, and D is incorrect as elements like O₂ are molecules.
Question 15 (C2)
Which dot-and-cross diagram shows the outer shell electrons in a molecule of carbon dioxide?
▶️Answer/Explanation
Answer: A
Explanation: The correct diagram shows carbon with 4 outer electrons forming double bonds with each oxygen (which each have 6 outer electrons). This gives each atom a full outer shell: carbon shares 4 pairs, each oxygen shares 2 pairs.
Question 16 (C3)
The equation for the combustion of magnesium is shown:
2Mg + O₂ → 2MgO
What is the mass of magnesium oxide formed from 12 g of magnesium?
A. 20 g
B. 24 g
C. 40 g
D. 80 g
▶️Answer/Explanation
Answer: A
Explanation: 1. Moles of Mg = mass/Mr = 12/24 = 0.5 mol 2. Equation shows 2:2 ratio, so 0.5 mol Mg produces 0.5 mol MgO 3. Mass of MgO = moles × Mr = 0.5 × (24+16) = 20 g
Question 17 (C4)
The diagram shows the electrolysis of lead(II) bromide using inert electrodes.
Which statement about this experiment is correct?
A. Electrode X is positively charged.
B. The colored fumes are produced at the negative electrode.
C. The electrolyte is lead(II) bromide.
D. The grey solid is lead(II) bromide.
▶️Answer/Explanation
Answer: C
Explanation: Lead(II) bromide is indeed the electrolyte being decomposed. The grey solid is lead metal (forms at cathode), and brown bromine vapor forms at the anode (positive electrode).
Question 18 (C6)
The ionic equation for the formation of chromium(III) ions is shown:
Cr → Cr³⁺ + 3e⁻
Which statement about chromium atoms is correct?
A. They are oxidized by gaining electrons.
B. They are oxidized by losing electrons.
C. They are reduced by gaining electrons.
D. They are reduced by losing electrons.
▶️Answer/Explanation
Answer: B
Explanation: Oxidation is loss of electrons (OIL RIG). Here chromium loses 3 electrons to form Cr³⁺ ions, so it’s being oxidized. The equation shows electron loss, not gain.
Question 19 (C7)
Which oxide is a neutral oxide?
A. CuO, because it reacts with sulfuric acid.
B. NO, because it is insoluble in acids and alkalis.
C. SiO₂, because it reacts with sodium hydroxide.
D. SO₂, because it dissolves in water.
▶️Answer/Explanation
Answer: B
Explanation: NO (nitrogen monoxide) is a neutral oxide as it doesn’t react with acids or bases. The other options are all wrong: CuO is basic, SiO₂ is acidic, and SO₂ forms acidic solutions.
Question 20 (C8)
Element X is in the third period and in Group II of the Periodic Table.
Element Y has the electronic structure 2,8,7.
Element Z forms an ionic compound with the formula Z₂(SO₄)₃.
Which row shows the order of metallic character?
▶️Answer/Explanation
Answer: D
Explanation: – X is Mg (metallic) – Y is Cl (non-metallic) – Z is Al (from Z₂(SO₄)₃ formula) Metallic character decreases from X to Z to Y, so Y (least) < Z < X (most).
Question 21 (C6.2)
Three methods for investigating rates of reaction are listed:
- Observe a colour change
- Use a gas syringe
- Use a balance
The equation for the reaction of magnesium and dilute hydrochloric acid is shown:
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
Which of the methods can be used to investigate the rate of this reaction?
A. 2 only
B. 1 and 2
C. 1 and 3
D. 2 and 3
▶️Answer/Explanation
Answer: D
Explanation:
- No color change occurs in this reaction, so method 1 cannot be used.
- The gas syringe can measure the volume of H2 gas produced over time (method 2).
- The balance can measure the mass loss as H2 gas escapes (method 3).
Therefore, only methods 2 and 3 are suitable for this reaction.
Question 22 (C9.2)
Which statement is not a reason why aluminium is used in aircraft manufacture?
A. It forms low density alloys
B. It is malleable
C. It is more reactive than iron
D. It is resistant to corrosion
▶️Answer/Explanation
Answer: C
Explanation: While aluminium is more reactive than iron (C), this is not a reason for its use in aircraft. Its key advantages are:
- Low density alloys reduce weight (A)
- Malleability allows shaping (B)
- Corrosion resistance increases durability (D)
Reactivity is irrelevant to its aircraft applications.
Question 23 (C10.2)
Which reactions occur in a car’s catalytic converter?
- 2CO + O2 → 2CO2
- 2NO + 2CO → N2 + 2CO2
- N2 + O2 → 2NO
A. 1 and 2 only
B. 1 and 3 only
C. 2 and 3 only
D. 1, 2 and 3
▶️Answer/Explanation
Answer: A
Explanation: Catalytic converters:
- Convert CO to CO2 (reaction 1)
- Reduce NO to N2 while oxidizing CO (reaction 2)
- Do NOT produce NO (reaction 3 is the reverse of what occurs)
Thus, only reactions 1 and 2 are correct.
Question 24 (C11.5)
The reaction equation for the production of ethanol by an addition reaction is shown:
C2H4 + H2O → C2H5OH
Which row describes the physical state of water and of ethanol in the reaction vessel?
| water | ethanol | |
|---|---|---|
| A | gas | gas |
| B | gas | liquid |
| C | liquid | gas |
| D | liquid | liquid |
▶️Answer/Explanation
Answer: A
Explanation: This industrial process uses:
- Ethene gas (C2H4)
- Steam (H2O gas) at high temperature (~300°C)
- The product ethanol initially forms as a gas before condensation
Thus, both reactants and product are in the gas phase during reaction.
Question 25 (C6.1)
When limestone is heated it thermally decomposes into lime. What is the word equation for this reaction?
A. calcium carbonate → calcium + carbon dioxide
B. calcium carbonate → calcium oxide + carbon dioxide
C. calcium hydrogencarbonate → calcium + carbon dioxide + water
D. calcium hydrogencarbonate → calcium oxide + carbon dioxide + water
▶️Answer/Explanation
Answer: B
Explanation: The thermal decomposition of limestone (calcium carbonate):
- Reactant: CaCO3 (calcium carbonate)
- Products: CaO (calcium oxide/lime) + CO2
- Hydrogencarbonate is not involved in this reaction
The correct equation is CaCO3 → CaO + CO2.
Question 26 (C11.3)
What are the uses of the fractions obtained from petroleum?
| gas oil | gasoline | refinery gas | |
|---|---|---|---|
| A | cooking | petrol fuel | diesel fuel |
| B | diesel fuel | heating | petrol fuel |
| C | diesel fuel | petrol fuel | cooking |
| D | petrol fuel | diesel fuel | heating |
▶️Answer/Explanation
Answer: C
Explanation: Petroleum fractions are used as:
- Gas oil: Diesel fuel for vehicles
- Gasoline: Petrol fuel for cars
- Refinery gas: Domestic cooking/heating
Option C correctly matches these uses.
Question 27 (C11.5)
Ethene is produced when decane, a large hydrocarbon, is heated with a catalyst. What is the name of this process?
A. combustion
B. cracking
C. displacement
D. neutralisation
▶️Answer/Explanation
Answer: B
Explanation: Cracking is:
- The thermal decomposition of long-chain hydrocarbons
- Breaks them into smaller molecules (like ethene)
- Requires high temperature and a catalyst (e.g. aluminum oxide)
- Different from combustion (burning) or other reaction types
Question 28 (P1.7)
A man carries a suitcase of mass of 30 kg. The area of contact with the man’s hand is 1.5 × 10-3 m2. The gravitational field strength g is 10 N/kg. What pressure is exerted on the man’s hand by the suitcase?
A. 0.045 Pa
B. 0.45 Pa
C. 20 000 Pa
D. 200 000 Pa
▶️Answer/Explanation
Answer: D
Explanation: Calculation steps:
- Weight = mass × g = 30 kg × 10 N/kg = 300 N
- Pressure = Force/Area = 300 N / 1.5 × 10-3 m2
- Pressure = 300 / 0.0015 = 200,000 Pa
The high pressure results from the small contact area.
Question 29 (P1.6.1)
An object of mass m moving with speed v has kinetic energy E. A second object, also of mass m, moves with speed v/2. What is the kinetic energy of the second object?
A. E/4
B. E/2
C. E
D. 2E
▶️Answer/Explanation
Answer: A
Explanation: Kinetic energy formula: E = ½mv2
- Original object: E = ½mv2
- Second object: E’ = ½m(v/2)2 = ½m(v2/4) = (½mv2)/4 = E/4
Kinetic energy is proportional to the square of velocity.
Question 30 (P1.6.4)
Which equation relates power P to energy change ΔE and time t?
A. P = ΔE2/(2 × t)
B. P = ½ × ΔE2 × t
C. P = ΔE/t
D. P = ΔE × t
▶️Answer/Explanation
Answer: C
Explanation: The fundamental definition of power is:
- Power = Energy transferred / Time taken
- Or P = ΔE/t
- Units: watts (W) = joules (J) / seconds (s)
This is the standard relationship between these quantities.
Question 31 (P1.6.3)
In which pair do both energy resources have the Sun as the source of their energy?
A. geothermal energy and tidal energy
B. hydroelectric energy and wind energy
C. nuclear energy and chemical energy stored in fuel
D. solar energy and nuclear energy
▶️Answer/Explanation
Answer: B
Explanation: Hydroelectric energy and wind energy both ultimately derive their energy from the Sun. The Sun drives the water cycle (creating hydroelectric potential) and creates wind patterns through uneven heating of the Earth’s surface. Geothermal and nuclear energy come from Earth’s internal heat and atomic nuclei respectively, while tidal energy comes from gravitational interactions.
Question 32 (P2.3.1)
A hot water tank is fitted with two identical heaters P and Q. Heater P is fitted above heater Q as shown. The tank is full of cold water.
When only heater Q is switched on, it takes a long time to heat the tank of water to 60°C. What happens to the cold water when only heater P is switched on?
A. All the water reaches 60°C in less time.
B. All the water reaches 60°C in the same time.
C. The water below heater P reaches 60°C in less time.
D. The water above heater P reaches 60°C in less time.
▶️Answer/Explanation
Answer: D
Explanation: When heater P is at the top, it heats the water above it first. Hot water is less dense and rises, creating convection currents that distribute heat slowly. The water above the heater will reach 60°C faster than when heater Q was used, but the tank as a whole won’t heat faster because convection still needs time to circulate the heat throughout the tank.
Question 33 (P3.1)
‘The number of crests on the surface of water that pass a particular point each second.’ Which property of a wave does this describe?
A. amplitude
B. frequency
C. speed
D. wavelength
▶️Answer/Explanation
Answer: B
Explanation: Frequency is defined as the number of wave crests passing a fixed point per second. Amplitude is the height of the wave, speed is how fast the wave travels, and wavelength is the distance between successive crests.
Question 34 (P3.2.3)
Which ray diagram represents the formation of a virtual image I of an object O?
▶️Answer/Explanation
Answer: A
Explanation: A virtual image is formed when diverging rays appear to come from a point behind the lens. In correct ray diagrams for virtual images, the rays diverge after passing through the lens and must be extended backward to locate the image. The image is upright and larger than the object when the object is within the focal length of a converging lens.
Question 35 (P4.2.2)
The current in a motor is 5.0A. How much charge passes through the motor in 1.0 minute?
A. 0.20 C
B. 5.0 C
C. 12 C
D. 300 C
▶️Answer/Explanation
Answer: D
Explanation: Using the formula Q = I × t, where I = 5.0A and t = 60 seconds (1 minute): Q = 5.0 × 60 = 300 C. The other options either use incorrect time conversions or calculation errors.
Question 36 (P4.2.5)
A lamp is connected to a 6.0 V battery. The current in the lamp is 1.5A.
How much energy is used by the lamp in 10 minutes?
A. 0.90 J
B. 40 J
C. 2400 J
D. 5400 J
▶️Answer/Explanation
Answer: D
Explanation: Energy = Power × Time = (V × I) × t = (6.0 × 1.5) × (10 × 60) = 9 × 600 = 5400 J. The other options come from incorrect calculations, such as not converting minutes to seconds or miscalculating the power.
Question 37 (P4.4)
A fuse is a safety device for use in an electrical circuit. The current in the circuit becomes greater than the rated value for the fuse. What happens?
A. The current decreases to zero.
B. The current decreases to the rated value for the fuse.
C. The thickness of the insulation around the wires increases.
D. The current is sent to the outer case of the appliance.
▶️Answer/Explanation
Answer: A
Explanation: When current exceeds the fuse’s rating, the fuse wire melts, breaking the circuit and reducing current to zero. This prevents damage to the circuit or appliance. Fuses don’t regulate current (B), affect wire insulation (C), or redirect current (D).
Question 38 (P4.5.3)
A current-carrying wire passes through a flat card. The arrow on each wire shows the direction of the current.
Which diagram shows the pattern of the magnetic field on the card and the direction of the magnetic field lines?
▶️Answer/Explanation
Answer: D
Explanation: The magnetic field around a current-carrying wire forms concentric circles, with direction given by the right-hand grip rule (thumb points in current direction, fingers curl in field direction). The field strength decreases with distance from the wire, shown by spacing between field lines.
Question 39 (P4.5.6)
A power station produces electricity at a voltage of 25 kV. Transformer 1 steps up the voltage to 400 kV for the transmission line.
At the other end of the transmission line, transformer 2 steps down 400 kV to 160 kV.
The turns ratio of a transformer is Np : Ns.
What is the turns ratio of transformer 1, and what is the turns ratio of transformer 2?
▶️Answer/Explanation
Answer: B
Explanation: For transformer 1: Vp/Vs = Np/Ns ⇒ 25/400 = 1/16. For transformer 2: 400/160 = 5/2. Step-up transformers have more turns on the secondary coil (Ns > Np), while step-down transformers have fewer turns on the secondary (Ns < Np).
Question 40 (P5.1)
The diagrams represent the nuclei of four different atoms V, W, X and Y.
Which two diagrams represent isotopes of the same element?
A. V and Y
B. W and X
C. X and Y
D. Y and W
▶️Answer/Explanation
Answer: C
Explanation: Isotopes are atoms of the same element (same number of protons) with different numbers of neutrons. Diagrams X and Y show nuclei with the same number of protons (same element) but different numbers of neutrons (different mass numbers), making them isotopes.