Question 1
1(a)(i) – B7.2 Digestive system
1(a)(ii) – B7.2 Digestive system
1(b) – B7.2 Digestive system
1(c) – B7.2 Digestive system
1(d) – B7.2 Digestive system
1(e)(i) – B7.2 Digestive system
1(e)(ii) – B7.2 Digestive system
1(f) – B7.2 Digestive system
1(g) – B7.2 Digestive system
1. (a) (i) State which animal in Table 1.1 has the largest number of teeth.
▶️Answer/Explanation
Answer: fox
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: The animal with the largest number of teeth in Table 1.1 is the fox, which has 42 teeth.
1. (a) (ii) Calculate the difference in the number of teeth between a human and an elephant as shown in Table 1.1.
▶️Answer/Explanation
Answer: 6
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: The difference in the number of teeth between a human (32 teeth) and an elephant (26 teeth) is 32 – 26 = 6.
1. (b) Circle the name of the outermost layer of a tooth.
▶️Answer/Explanation
Answer: enamel
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: The outermost layer of a tooth is called the enamel, which protects the tooth from decay.
1. (c) State the type of teeth responsible for grinding food.
▶️Answer/Explanation
Answer: molar / pre molar
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: The molars and premolars are responsible for grinding food during the chewing process.
1. (d) Describe one way to take care of teeth.
▶️Answer/Explanation
Answer: brushing / using toothpaste / (regular) visits to dentist / consume less sugary food or drink
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: One way to take care of teeth is by brushing regularly with toothpaste, which helps remove plaque and prevent tooth decay. Regular visits to the dentist and reducing sugary food intake also help maintain dental health.
1. (e) (i) Identify the letter from Fig. 1.1 that represents where:
egestion occurs ……
the most absorption occurs ……
ingestion occurs. ……
▶️Answer/Explanation
Answer: D ; E ; H
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: In Fig. 1.1, egestion occurs at D, the most absorption occurs at E, and ingestion occurs at H.
1. (e) (ii) State the name of part C in Fig. 1.1.
▶️Answer/Explanation
Answer: pancreas
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: Part C in Fig. 1.1 is the pancreas, which produces digestive enzymes and insulin.
1. (f) Complete the definition of digestion.
Digestion is the …… of large, insoluble food molecules into small, water-soluble molecules using …… and chemical processes.
▶️Answer/Explanation
Answer: break(ing) down ; mechanical
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: Digestion is the process of breaking down large, insoluble food molecules into small, water-soluble molecules using mechanical and chemical processes.
1. (g) After the food is digested, nutrients pass into the blood. State the part of the blood that transports soluble nutrients.
▶️Answer/Explanation
Answer: plasma
Sub-topic Code: B1.1 (Characteristics of living organisms)
Detailed Solution: The part of the blood that transports soluble nutrients is the plasma, which is the liquid component of blood.
Question 2
2(a)(i) – C11.3 Fuels
2(a)(ii) – C11.3 Fuels
2(b) – C2.5 Simple molecules and covalent bonds
2(c)(i) – C5.1 Exothermic and endothermic reactions
2(c)(ii) – C5.1 Exothermic and endothermic reactions
2(c)(iii) – C5.1 Exothermic and endothermic reactions
2(d)(i) – C11.4 Alkanes
2(d)(ii) – C11.5 Alkenes
2. (a) (i) State what is meant by the term hydrocarbon.
▶️Answer/Explanation
Answer: contains carbon and hydrogen (atoms); only
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: A hydrocarbon is a compound that contains only carbon and hydrogen atoms.
2. (a) (ii) State the fossil fuel whose main constituent is methane.
▶️Answer/Explanation
Answer: natural gas
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: The fossil fuel whose main constituent is methane is natural gas.
2. (b) Complete the dot-and-cross diagram of a molecule of methane in Fig. 2.1. Include the symbols for the chemical elements. Show outer shell electrons only.
▶️Answer/Explanation
Answer: correct symbols; 4 bonding pairs and all else correct
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: The dot-and-cross diagram for methane (CH₄) should show one carbon atom with four hydrogen atoms, each sharing one electron with the carbon atom. The carbon atom has four outer shell electrons, and each hydrogen atom has one outer shell electron.
2. (c) (i) The combustion of methane is an exothermic reaction. State what is meant by exothermic.
▶️Answer/Explanation
Answer: gives out (thermal) energy
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: An exothermic reaction is a chemical reaction that releases energy in the form of heat or light.
2. (c) (ii) State the two products of the complete combustion of methane in oxygen.
▶️Answer/Explanation
Answer: carbon dioxide; water
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: The complete combustion of methane in oxygen produces carbon dioxide (CO₂) and water (H₂O).
2. (c) (iii) During the incomplete combustion of methane, carbon monoxide is sometimes made. Describe one adverse effect of carbon monoxide on the health of humans.
▶️Answer/Explanation
Answer: death / poisoning / CO is toxic / reduces the oxygen carrying capacity of the red blood cells
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: Carbon monoxide is toxic and can bind to hemoglobin in red blood cells, reducing their ability to carry oxygen, which can lead to poisoning or death.
2. (d) (i) State the difference in structure between an alkane and an alkene.
▶️Answer/Explanation
Answer: alkene contains a double bond / alkane only has single bonds
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: The main difference between an alkane and an alkene is that alkenes contain at least one carbon-carbon double bond, while alkanes contain only single bonds.
2. (d) (ii) Describe a chemical test that distinguishes between an alkane and an alkene. Describe the observations for a positive result of the test in each case.
▶️Answer/Explanation
Answer: aqueous bromine; alkane – no colour change; alkene – orange to colourless / goes colourless
Sub-topic Code: C2.1 (Hydrocarbons)
Detailed Solution: A chemical test to distinguish between an alkane and an alkene is the bromine water test. Alkanes do not react with bromine water, so there is no color change. Alkenes react with bromine water, causing the orange color to disappear, indicating the presence of a double bond.
Question 3
3(a)(i) – P3.3 Electromagnetic spectrum
3(a)(ii) – P3.3 Electromagnetic spectrum
3(b)(i) – P3.2.2 Refraction of light
3(b)(ii) – P3.2.2 Refraction of light
3(b)(iii) – P3.2.2 Refraction of light
3(b)(iv) – P1.7 Pressure
3(b)(v) – P1.4 Density
3(c)(i) – P5.2.2 The three types of nuclear emission
3(c)(ii) – P5.2.2 The three types of nuclear emission
3(c)(iii) – P5.2.2 The three types of nuclear emission
3. (a) (i) State which wave in the electromagnetic spectrum has the highest frequency.
▶️Answer/Explanation
Answer: γ-ray
Sub-topic Code: P5.1 (Electromagnetic Spectrum)
Detailed Solution: Gamma rays (γ-rays) have the highest frequency in the electromagnetic spectrum, making them the most energetic type of electromagnetic radiation.
3. (a) (ii) State which wave is emitted by a remote control for a television.
▶️Answer/Explanation
Answer: infrared
Sub-topic Code: P5.1 (Electromagnetic Spectrum)
Detailed Solution: Remote controls for televisions emit infrared waves, which are used to send signals to the TV.
3. (b) (i) State the effect shown by the ray of light at B in Fig. 3.1.
▶️Answer/Explanation
Answer: refraction
Sub-topic Code: P6.1 (Light)
Detailed Solution: The ray of light at B undergoes refraction, which is the bending of light as it passes from one medium (air) to another (glass).
3. (b) (ii) State the name of the line labelled PQ in Fig. 3.1.
▶️Answer/Explanation
Answer: normal
Sub-topic Code: P6.1 (Light)
Detailed Solution: The line labelled PQ is called the normal, which is an imaginary line perpendicular to the surface at the point where the light ray enters the glass block.
3. (b) (iii) State the value of angle x in Fig. 3.1.
▶️Answer/Explanation
Answer: 45°
Sub-topic Code: P6.1 (Light)
Detailed Solution: Angle x is the angle of refraction, which is given as 45° in the diagram.
3. (b) (iv) The glass block in Fig. 3.1 is resting on a bench. The glass block exerts a pressure on the bench. State the two variables that must be measured to determine the pressure exerted.
▶️Answer/Explanation
Answer: force / mass / weight; area
Sub-topic Code: P2.1 (Forces)
Detailed Solution: To calculate pressure, you need to measure the force (or weight) exerted by the glass block and the area of contact between the block and the bench. Pressure is calculated as force divided by area.
3. (b) (v) The mass of the glass block is 156 g. The volume of the glass block is 60.0 cm³. Calculate the density of the glass block.
▶️Answer/Explanation
Answer: 2.60 g/cm³
Sub-topic Code: P4.1 (Density)
Detailed Solution: Density is calculated as mass divided by volume. For the glass block, density = 156 g / 60.0 cm³ = 2.60 g/cm³.
3. (c) (i) Place α-particles, β-particles, and γ-rays in order of their ionising ability.
▶️Answer/Explanation
Answer: α, β, γ
Sub-topic Code: P12.1 (Radioactivity)
Detailed Solution: α-particles have the highest ionising ability, followed by β-particles, and γ-rays have the least ionising ability.
3. (c) (ii) State which one of these radiations is negatively charged.
▶️Answer/Explanation
Answer: β
Sub-topic Code: P12.1 (Radioactivity)
Detailed Solution: β-particles are negatively charged, as they are high-energy electrons.
3. (c) (iii) State which one of these radiations is the most penetrating.
▶️Answer/Explanation
Answer: γ
Sub-topic Code: P12.1 (Radioactivity)
Detailed Solution: γ-rays are the most penetrating type of radiation, as they can pass through most materials, including thick layers of concrete or lead.
Question 4
4(a)(i) – B15.3 Sexual reproduction in plants
4(a)(ii) – B15.3 Sexual reproduction in plants
4(b) – B15.3 Sexual reproduction in plants
4(c) – B15.1 Asexual reproduction
4(d) – B1.1 Characteristics of living organisms
4. (a) (i) Complete Table 4.1 by identifying the function of the parts labelled A–E in Fig. 4.1.
▶️Answer/Explanation
Answer: D (attracts pollinators); E (where pollination occurs); A (produces pollen)
Sub-topic Code: B11.1 (Reproduction in Plants)
Detailed Solution: In Fig. 4.1, part D attracts pollinators, part E is where pollination occurs, and part A produces pollen.
4. (a) (ii) State the name of part B in Fig. 4.1.
▶️Answer/Explanation
Answer: filament
Sub-topic Code: B11.1 (Reproduction in Plants)
Detailed Solution: Part B in Fig. 4.1 is the filament, which supports the anther in a flower.
4. (b) Complete the sentence to describe fertilisation in plants.
Fertilisation occurs when a pollen nucleus fuses with the nucleus in the ……
▶️Answer/Explanation
Answer: ovule
Sub-topic Code: B11.1 (Reproduction in Plants)
Detailed Solution: Fertilisation in plants occurs when a pollen nucleus fuses with the nucleus in the ovule, leading to the formation of a zygote.
4. (c) State two ways asexual reproduction is different from sexual reproduction.
▶️Answer/Explanation
Answer: involves only one parent; produces genetically identical offspring
Sub-topic Code: B11.1 (Reproduction in Plants)
Detailed Solution: Asexual reproduction involves only one parent and produces genetically identical offspring, while sexual reproduction involves two parents and produces genetically diverse offspring.
4. (d) Tick (✓) two boxes that each show a characteristic of all living organisms.
▶️Answer/Explanation
Answer: excretion; sensitivity
Sub-topic Code: B1.1 (Characteristics of Living Organisms)
Detailed Solution: Excretion and sensitivity are characteristics of all living organisms. Excretion is the removal of waste products, and sensitivity is the ability to respond to stimuli.
Question 5
5(a)(i) – C2.2 Atomic structure and the Periodic Table
5(a)(ii) – C2.2 Atomic structure and the Periodic Table
5(a)(iii) – C2.2 Atomic structure and the Periodic Table
5(b) – C12.5 Identification of ions and gases
5(c)(i) – C9.3 Alloys and their properties
5(c)(ii) – C9.3 Alloys and their properties
5(c)(iii) – C9.5 Corrosion of metals
5(c)(iv) – C9.5 Corrosion of metals
5. (a) (i) State the number of electrons in an atom of iron with a proton number of 26 and a nucleon number of 56.
▶️Answer/Explanation
Answer: 26
Sub-topic Code: C16.1 (Atomic Structure)
Detailed Solution: In a neutral atom, the number of electrons is equal to the number of protons. Since the proton number is 26, the number of electrons is also 26.
5. (a) (ii) State the number of neutrons in this atom of iron.
▶️Answer/Explanation
Answer: 30
Sub-topic Code: C16.1 (Atomic Structure)
Detailed Solution: The number of neutrons is calculated as nucleon number minus proton number. For this atom of iron, neutrons = 56 – 26 = 30.
5. (a) (iii) Another atom of iron has a nucleon number of 54. State the proton number of this atom of iron.
▶️Answer/Explanation
Answer: 26
Sub-topic Code: C16.1 (Atomic Structure)
Detailed Solution: The proton number of an element is constant. For iron, the proton number is always 26, regardless of the nucleon number.
5. (b) State the test for aqueous iron(III) ions (Fe³⁺) and give the observation for a positive result.
▶️Answer/Explanation
Answer: sodium hydroxide solution; orange / brown ppt
Sub-topic Code: C9.1 (Chemical Tests)
Detailed Solution: The test for iron(III) ions involves adding sodium hydroxide solution. A positive result is indicated by the formation of an orange or brown precipitate of iron(III) hydroxide.
5. (c) (i) Define the term alloy.
▶️Answer/Explanation
Answer: mixture of metals / mixture of a metal and another element
Sub-topic Code: C25.1 (Alloys)
Detailed Solution: An alloy is a mixture of metals or a mixture of a metal with another element, designed to improve the properties of the base metal.
5. (c) (ii) State one use for stainless steel.
▶️Answer/Explanation
Answer: cutlery / chemical plant
Sub-topic Code: C25.1 (Alloys)
Detailed Solution: Stainless steel is commonly used in cutlery and chemical plants due to its resistance to corrosion and durability.
5. (c) (iii) State the two conditions needed for the rusting of iron.
▶️Answer/Explanation
Answer: (presence of) oxygen; (presence of) water
Sub-topic Code: C21.1 (Redox Reactions)
Detailed Solution: Rusting of iron requires the presence of both oxygen and water. These two conditions facilitate the oxidation of iron to form iron oxide (rust).
5. (c) (iv) Describe and explain one method of rust prevention.
▶️Answer/Explanation
Answer: painting / galvanising / plating / greasing; relevant explanation for method chosen (e.g. stops water / oxygen)
Sub-topic Code: C21.1 (Redox Reactions)
Detailed Solution: One method of rust prevention is painting, which creates a barrier that prevents oxygen and water from reaching the iron surface. Galvanising, plating, and greasing are other methods that achieve the same goal.
Question 6
6(a)(i) – P3.4 Sound
6(a)(ii) – P3.4 Sound
6(a)(iii) – P3.4 Sound
6(b)(i) – P1.2 Motion
6(b)(ii) – P1.2 Motion
6(b)(iii) – P1.2 Motion
6(c) – P2.2.2 Melting, boiling and evaporation
6. (a) (iii) The sound waves travel 80 m. The speed of sound in water is 1600 m/s. Calculate the time taken for a sound wave to travel 80 m in water.
▶️Answer/Explanation
Answer: 0.05 s
Sub-topic Code: P7.1 (Sound)
Detailed Solution: Time = distance / speed = 80 m / 1600 m/s = 0.05 s.
6. (b) (i) Describe the motion of the dolphin between time = 0 and time = 5 s in Fig. 6.2.
▶️Answer/Explanation
Answer: accelerating / speed increasing
Sub-topic Code: P1.1 (Motion)
Detailed Solution: The dolphin is accelerating, as its speed increases over time from 0 to 5 seconds.
6. (b) (ii) State the maximum speed of the dolphin as shown on the graph.
▶️Answer/Explanation
Answer: 6 m/s
Sub-topic Code: P1.1 (Motion)
Detailed Solution: The maximum speed of the dolphin, as shown on the graph, is 6 m/s.
6. (b) (iii) Calculate the distance travelled by the dolphin between time = 15 s and time = 30 s.
▶️Answer/Explanation
Answer: 45.0 m
Sub-topic Code: P1.1 (Motion)
Detailed Solution: The distance travelled is the area under the speed-time graph between 15 s and 30 s. This is a triangle with base = 15 s and height = 6 m/s. Area = 0.5 × base × height = 0.5 × 15 × 6 = 45.0 m.
6. (c) Describe the process of evaporation using ideas about particles.
▶️Answer/Explanation
Answer: fast moving / most energetic particles; escape from surface of liquid
Sub-topic Code: P4.1 (Thermal Properties)
Detailed Solution: Evaporation occurs when the most energetic particles at the surface of a liquid gain enough energy to escape into the gas phase. This leaves the remaining liquid cooler.
Question 7
7(a)(i) – B18.3 Carbon cycle
7(a)(ii) – B12.1 Respiration
7(b) – B6.1 Photosynthesis
7(c)(i) – B18.2 Food chains and food webs
7(c)(ii) – B18.2 Food chains and food webs
7. (a) (i) Draw an arrow on Fig. 7.1 to represent the process of decomposition.
▶️Answer/Explanation
Answer: arrow drawn between dead organisms and carbon dioxide in the atmosphere
Sub-topic Code: B14.1 (Carbon Cycle)
Detailed Solution: Decomposition is the breakdown of dead organisms by decomposers, releasing carbon dioxide back into the atmosphere.
7. (a) (ii) Describe the process of respiration.
▶️Answer/Explanation
Answer: chemical reaction that happens in cells; releases energy; ref to glucose and oxygen as reactants; ref to carbon dioxide and water as products
Sub-topic Code: B6.1 (Respiration)
Detailed Solution: Respiration is a chemical reaction that occurs in cells, where glucose and oxygen react to release energy, producing carbon dioxide and water as by-products.
7. (b) State three requirements for photosynthesis.
▶️Answer/Explanation
Answer: carbon dioxide; water; chlorophyll; light; warm temperature
Sub-topic Code: B6.1 (Photosynthesis)
Detailed Solution: Photosynthesis requires carbon dioxide, water, chlorophyll, light, and a warm temperature to occur efficiently.
7. (c) (i) Circle the two words from the list that can be used to describe the sheep in Fig. 7.2.
▶️Answer/Explanation
Answer: herbivore; consumer
Sub-topic Code: B13.1 (Food Chains and Webs)
Detailed Solution: The sheep is a herbivore (it eats plants) and a consumer (it obtains energy by consuming other organisms).
7. (c) (ii) Identify the tertiary consumer in Fig. 7.2.
▶️Answer/Explanation
Answer: wolf
Sub-topic Code: B13.1 (Food Chains and Webs)
Detailed Solution: The wolf is the tertiary consumer in the food chain, as it feeds on the fox, which is a secondary consumer.
Question 8
8(a)(i) – C2.5 Simple molecules and covalent bonds
8(a)(ii) – C2.5 Simple molecules and covalent bonds
8(a)(iii) – C10.2 Air quality and climate
8(b)(i) – C2.5 Simple molecules and covalent bonds
8(b)(ii) – C2.5 Simple molecules and covalent bonds
8(c) – C12.1 Experimental design
8(d)(i) – C7.3 Preparation of salts
8(d)(ii) – C7.3 Preparation of salts
8(d)(iii) – C6.2 Rate of reaction
8. (a) (i) Identify two molecules from Table 8.1 that are elements.
▶️Answer/Explanation
Answer: Cl₂; H₂
Sub-topic Code: C2.1 (Elements and Compounds)
Detailed Solution: Cl₂ (chlorine) and H₂ (hydrogen) are elements because they consist of only one type of atom.
8. (a) (ii) Identify one molecule from Table 8.1 that is diatomic.
▶️Answer/Explanation
Answer: HCl / Cl₂ / H₂
Sub-topic Code: C2.1 (Elements and Compounds)
Detailed Solution: HCl (hydrogen chloride), Cl₂ (chlorine), and H₂ (hydrogen) are diatomic molecules because they consist of two atoms bonded together.
8. (a) (iii) Identify one molecule from Table 8.1 which is a greenhouse gas.
▶️Answer/Explanation
Answer: CO₂
Sub-topic Code: C2.1 (Elements and Compounds)
Detailed Solution: CO₂ (carbon dioxide) is a greenhouse gas because it traps heat in the Earth’s atmosphere, contributing to global warming.
8. (b) (i) State the names of the two elements present in a molecule of ammonia, NH₃.
▶️Answer/Explanation
Answer: nitrogen; hydrogen
Sub-topic Code: C2.1 (Elements and Compounds)
Detailed Solution: Ammonia (NH₃) consists of nitrogen and hydrogen atoms.
8. (b) (ii) Determine the total number of atoms in a molecule of ammonia, NH₃.
▶️Answer/Explanation
Answer: 4
Sub-topic Code: C2.1 (Elements and Compounds)
Detailed Solution: A molecule of ammonia (NH₃) contains 1 nitrogen atom and 3 hydrogen atoms, totaling 4 atoms.
8. (c) State the meaning of the term solvent.
▶️Answer/Explanation
Answer: a (liquid) in which other substances dissolve
Sub-topic Code: C8.1 (Solutions)
Detailed Solution: A solvent is a liquid in which other substances (solutes) dissolve to form a solution.
8. (d) (i) State which salt is produced when dilute hydrochloric acid reacts with calcium carbonate.
▶️Answer/Explanation
Answer: calcium chloride
Sub-topic Code: C9.1 (Chemical Reactions)
Detailed Solution: When dilute hydrochloric acid reacts with calcium carbonate, calcium chloride is produced along with carbon dioxide and water.
8. (d) (ii) Suggest a method of obtaining a sample of the dry salt from this salt solution.
▶️Answer/Explanation
Answer: evaporation
Sub-topic Code: C8.1 (Solutions)
Detailed Solution: To obtain a dry sample of the salt, the water can be evaporated from the solution, leaving behind the solid salt.
8. (d) (iii) Suggest two ways of increasing the rate of reaction between calcium carbonate and dilute hydrochloric acid.
▶️Answer/Explanation
Answer: increase temperature; increase surface area / decrease particle size; increase concentration of acid
Sub-topic Code: C9.1 (Chemical Reactions)
Detailed Solution: The rate of reaction can be increased by raising the temperature, increasing the surface area of the calcium carbonate (e.g., by using smaller particles), or increasing the concentration of the hydrochloric acid.
Question 9
9(a) – P2.3.3 Radiation
9(b) – P2.1.1 States of matter
9(c)(i) – P4.2.2 Electric current
9(c)(ii) – P4.3.2 Series and parallel circuits
9(d) – P4.5.5 The d.c. motor
9. (a) On Fig. 9.1, draw one straight arrow to show the movement of the air cooled by the freezing compartment.
▶️Answer/Explanation
Answer: vertical arrow downwards
Sub-topic Code: P4.1 (Thermal Properties)
Detailed Solution: The cooled air moves downwards due to its higher density compared to the warmer air in the refrigerator.
9. (b) Describe two differences between the particle arrangement in a liquid and in a solid as shown in Fig. 9.2.
▶️Answer/Explanation
Answer: solid has regular arrangement / liquid has irregular arrangement; particles are further apart in a liquid
Sub-topic Code: P4.1 (States of Matter)
Detailed Solution: In a solid, particles are arranged in a regular, fixed pattern, while in a liquid, the arrangement is irregular. Additionally, particles in a liquid are further apart compared to those in a solid.
9. (c) (i) Show that the resistance of the lamp is 6000 Ω.
▶️Answer/Explanation
Answer: \( R = \frac{V}{I} = \frac{240}{0.04} = 6000 \, \Omega \)
Sub-topic Code: P9.1 (Electric Circuits)
Detailed Solution: Using Ohm’s Law, \( R = \frac{V}{I} \), where \( V = 240 \, V \) and \( I = 0.04 \, A \). Thus, \( R = \frac{240}{0.04} = 6000 \, \Omega \).
9. (c) (ii) State the correct value for the combined resistance of two lamps connected in parallel and explain your answer.
▶️Answer/Explanation
Answer: 3000 Ω; combined resistance of two resistors in parallel is less than that of either resistor by itself
Sub-topic Code: P9.1 (Electric Circuits)
Detailed Solution: When two resistors of equal resistance (6000 Ω) are connected in parallel, the combined resistance is half of one resistor, i.e., 3000 Ω. This is because the total resistance in parallel is always less than the smallest individual resistance.
9. (d) State two other ways to increase the turning effect of the motor.
▶️Answer/Explanation
Answer: increase current; increase number of turns on coil
Sub-topic Code: P11.1 (Electromagnetism)
Detailed Solution: The turning effect of a motor can be increased by increasing the current flowing through the coil or by increasing the number of turns on the coil, which increases the magnetic field strength.
Question 10
10(a)(i) – B2.1 Cell structure
10(a)(ii) – B2.1 Cell structure
10(a)(iii) – B2.1 Cell structure
10(a)(iv) – B2.1 Cell structure
10(b) – B2.2 Size of specimens
10(c) – B9.4 Blood
10. (a) (iv) State one function of root hair cells.
▶️Answer/Explanation
Answer: 
absorption (of water / mineral ions)
Sub-topic Code: B2.1 (Cell Structure)
Detailed Solution: Root hair cells are specialized for absorbing water and mineral ions from the soil.
10. (b) Calculate how many times longer this plant cell is compared to this animal cell.
▶️Answer/Explanation
Answer: 2.5
Sub-topic Code: B2.1 (Cell Structure)
Detailed Solution: The plant cell is 0.05 mm long, and the animal cell is 0.02 mm long. The plant cell is \( \frac{0.05}{0.02} = 2.5 \) times longer than the animal cell.
10. (c) State which type of animal cell transports oxygen.
▶️Answer/Explanation
Answer: red blood cell
Sub-topic Code: B8.1 (Circulatory System)
Detailed Solution: Red blood cells are specialized for transporting oxygen from the lungs to the rest of the body.
Question 11
11(a)(i) – C8.2 Group I properties
11(a)(ii) – C8.2 Group I properties
11(b) – C9.1 Properties of metals
11(c) – C4.1 Electrolysis
11. (a) (i) Identify three metals from Table 11.1 that have only one electron in their outer shell as a neutral atom.
▶️Answer/Explanation
Answer: lithium; potassium; sodium
Sub-topic Code: C16.1 (Atomic Structure)
Detailed Solution: Lithium, potassium, and sodium are Group I metals, which have only one electron in their outer shell as neutral atoms.
11. (a) (ii) Identify the two metals from Table 11.1 that are Group II metals.
▶️Answer/Explanation
Answer: calcium; magnesium
Sub-topic Code: C16.1 (Atomic Structure)
Detailed Solution: Calcium and magnesium are Group II metals, which have two electrons in their outer shell as neutral atoms.
11. (b) State three general physical properties that distinguish metals from non-metals.
▶️Answer/Explanation
Answer: good thermal conductors; good electrical conductors; (relatively) high melting point / boiling point; malleable
Sub-topic Code: C16.1 (Metals and Non-Metals)
Detailed Solution: Metals are good thermal and electrical conductors, have relatively high melting and boiling points, and are malleable (can be hammered into shape).
11. (c) Use words from the list to complete the description of electroplating.
▶️Answer/Explanation
Answer: negative; positive; electrolyte
Sub-topic Code: C19.1 (Electrolysis)
Detailed Solution: In electroplating, the object to be plated is connected to the negative terminal (cathode), the piece of copper is connected to the positive terminal (anode), and the aqueous copper(II) sulfate acts as the electrolyte.
Question 12
12(a)(i) – P1.5.1 Effects of forces
12(a)(ii) – P1.5.1 Effects of forces
12(b) – P1.6.1 Energy
12(c) – P2.3.3 Radiation
12(d) – P4.1 Simple phenomena of magnetism
12(e) – C10.2 Air quality and climate
12(f) – P2.1.2 Particle model
12. (a) (i) State which force is the weight of the bus in Fig. 12.1.
▶️Answer/Explanation
Answer: R
Sub-topic Code: P2.1 (Forces)
Detailed Solution: The weight of the bus is the force acting vertically downwards, which is represented by force R in Fig. 12.1.
12. (a) (ii) Force Q is 500,000 N. State the size of force S.
▶️Answer/Explanation
Answer: 500,000 N
Sub-topic Code: P2.1 (Forces)
Detailed Solution: Since the bus is traveling at constant speed, the forces are balanced. Therefore, force S (air resistance) must be equal to force Q (engine force), which is 500,000 N.
12. (b) The bus uses stored chemical energy from fuel to accelerate up a hill. Some of this energy is transferred to thermal energy and sound energy. State two other forms of energy transferred to the bus as it accelerates up the hill.
▶️Answer/Explanation
Answer: kinetic energy; gravitational potential energy
Sub-topic Code: P3.1 (Energy Transfers)
Detailed Solution: As the bus accelerates up the hill, its kinetic energy (due to motion) and gravitational potential energy (due to height) increase.
12. (c) State the method of thermal energy transfer between the Sun and the Earth.
▶️Answer/Explanation
Answer: radiation
Sub-topic Code: P4.1 (Thermal Energy Transfer)
Detailed Solution: Thermal energy from the Sun is transferred to the Earth by radiation, which does not require a medium and can travel through the vacuum of space.
12. (d) Describe one difference between the magnetic properties of soft iron and the magnetic properties of steel.
▶️Answer/Explanation
Answer: iron magnetises quicker / iron loses magnetism quicker
Sub-topic Code: P11.1 (Magnetism)
Detailed Solution: Soft iron magnetizes and demagnetizes more quickly than steel, making it suitable for temporary magnets, while steel retains magnetism for longer.
12. (e) Name one other non-renewable energy source and one renewable energy source.
▶️Answer/Explanation
Answer: coal / natural gas; hydroelectric / solar / tidal / waves / geothermal / biogas / wind
Sub-topic Code: P3.1 (Energy Resources)
Detailed Solution: Non-renewable energy sources include coal and natural gas, while renewable energy sources include hydroelectric, solar, tidal, waves, geothermal, biogas, and wind energy.
12. (f) Describe how the motion of the molecules inside the tyres changes as the air warms up.
▶️Answer/Explanation
Answer: gain KE / move faster
Sub-topic Code: P4.1 (Thermal Properties)
Detailed Solution: As the air inside the tyres warms up, the molecules gain kinetic energy and move faster, increasing the pressure inside the tyres.