SECTION B: THEORY QUESTIONS (50 marks) Instructions: Answer all four questions. Question 1 is compulsory. You may choose any three from questions 2, 3, and 4.

Here are the solutions to your questions. Multiple Choice Questions (44-50): 44. Step 1: Identify what constitutes an electronic component. Resistors, capacitors, and transistors are fundamental building blocks of electronic circuits. Step 2: Evaluate the options. A thermometer is a device used to measure temperature, often containing electronic components, but it is not itself a basic electronic component like the others. Answer: D. Thermometer 45. Step 1: Recall the basic function of a resistor. Resistors are designed to oppose the flow of electric current. Step 2: Compare with the given options. Storing energy is for capacitors, converting AC to DC is for rectifiers (diodes), and amplifying signals is for transistors. Restricting current flow directly matches the function of a resistor. Answer: B. Restrict the flow of electric current 46. Step 1: Recall the basic function of a capacitor. Capacitors store electrical energy in an electric field. Step 2: Evaluate the options. Option B accurately describes the dual role of capacitors in storing energy and smoothing voltage fluctuations (e.g., in power supplies). Answer: B. Store electrical energy and smooth voltage fluctuations 47. Step 1: Understand the fundamental property of a diode. A diode is a semiconductor device that allows current to flow easily in one direction (forward bias) and blocks it in the opposite direction (reverse bias). Step 2: Relate this property to its primary uses. While converting AC to DC (rectification) is a common application, it is a direct consequence of the diode's ability to allow current in only one direction. Therefore, allowing current to flow in only one direction is the most fundamental primary use. Answer: D. Allow current to flow in only one direction 48. Step 1: Recall the functions of the listed components. Resistors restrict current, capacitors store energy, inductors store energy in a magnetic field. Step 2: Identify the component known for amplification and switching. Transistors are semiconductor devices specifically designed for these purposes. Answer: C. Transistor 49. Step 1: Understand what an LED is. LED stands for Light-Emitting Diode. Step 2: Infer its function from its name. It emits light when electrical current passes through it. Answer: B. Electrical energy into light energy 50. Step 1: List the typical components of a solar panel system. These include solar panels (PV modules), an inverter (to convert DC from panels to AC for household use), and a mounting structure. Step 2: Identify the outlier. A combustion engine is used in traditional generators or vehicles and is not a standard component of a solar photovoltaic system. Answer: C. Combustion engine SECTION B: THEORY QUESTIONS (50 marks) Question 1 (Compulsory) - 20 marks 1.a) Distinguish between sexual and asexual reproduction in plants. (8 marks) Sexual Reproduction: Involves the fusion of male and female gametes, typically from two parent plants (or different parts of the same plant). It leads to offspring with genetic variation, often through seeds. Asexual Reproduction: Involves a single parent plant producing offspring that are genetically identical clones of the parent. It does not involve the fusion of gametes and can occur through vegetative parts like stems, roots, or leaves. 1.b) Describe the process of fertilisation in flowering plants and explain why it is important for plant reproduction. (12 marks) Step 1: Pollination. Pollen grains, containing male gametes, are transferred from the anther to the stigma of a flower. Step 2: Pollen Germination. Upon landing on a compatible stigma, the pollen grain absorbs moisture and nutrients, then germinates to form a pollen tube. Step 3: Pollen Tube Growth. The pollen tube grows down through the style, guided by chemical signals, towards the ovule located within the ovary. Step 4: Double Fertilisation. The pollen tube penetrates the ovule, releasing two male gametes. One male gamete fuses with the egg cell to form a diploid zygote, which develops into the embryo. The other male gamete fuses with the central cell (containing two polar nuclei) to form a triploid endosperm, which provides nourishment for the developing embryo. Importance: Fertilisation is crucial because it leads to the formation of a zygote (which develops into a new plant embryo) and endosperm (food source for the embryo), both enclosed within a seed*. Seeds allow for dispersal, dormancy, and protection of the embryo, ensuring the survival and propagation of the plant species. It also introduces genetic variation, which is vital for adaptation to changing environments. Question 2 - 15 marks 2.a) Draw and label the structure of the female reproductive system, identifying at least six key parts. (8 marks) (As an AI, I cannot draw. However, here are the key parts that should be labeled in a diagram of the female reproductive system):* • Ovaries (produce eggs and hormones) • Oviducts (Fallopian tubes) (site of fertilization, transport eggs) • Uterus (womb) (site of fetal development) • Endometrium (lining of the uterus) • Cervix (neck of the uterus, opens into the vagina) • Vagina (birth canal, receives sperm) 2.b) Explain the role of the placenta in human reproduction and describe how it protects the developing foetus. (7 marks) Role of the Placenta: The placenta is a temporary organ that develops in the uterus during pregnancy. It serves as the primary interface between the mother and the developing fetus. Its main roles include: • Nutrient and Oxygen Exchange: Facilitates the transfer of essential nutrients (glucose, amino acids, fatty acids, vitamins, minerals) and oxygen from the mother's blood to the fetal blood. • Waste Removal: Transfers metabolic waste products (like urea and carbon dioxide) from the fetal blood to the mother's blood for excretion. • Hormone Production: Produces vital hormones such as progesterone, estrogen, and human chorionic gonadotropin (hCG), which are essential for maintaining pregnancy. Protection of the Fetus: The placenta protects the developing fetus in several ways: • Barrier Function: It acts as a selective barrier, preventing many harmful substances, bacteria, and some viruses from passing from the mother to the fetus. • Immune Protection: It transfers maternal antibodies (e.g., IgG) to the fetus, providing passive immunity against various diseases. • Stable Environment: It helps maintain a stable internal environment for the fetus by regulating temperature and fluid balance. Question 3 - 15 marks 3.a) Define force and explain why it is classified as a vector quantity. Give two examples of forces that act on objects in everyday life. (7 marks) Definition of Force: A force is a push or a pull that can cause an object to accelerate (change its velocity), deform, or change its state of motion. Vector Quantity: Force is classified as a vector quantity because it possesses both magnitude (how strong the push or pull is, measured in Newtons) and direction* (the way the push or pull is applied). To fully describe a force, both its strength and the direction in which it acts must be specified. Examples of Forces in Everyday Life: • Gravitational Force (Weight): The force exerted by the Earth on objects, pulling them downwards (e.g., an apple falling from a tree). • Frictional Force: The force that opposes motion between two surfaces in contact (e.g., the force that slows down a rolling ball). 3.b) A car with a mass of 1500 kg accelerates from 0 m/s to 20 m/s in 10 seconds. Calculate: (i) The acceleration of the car (3 marks) (ii) The net force acting on the car using Newton's second law (F = ma) (5 marks) Given: Mass, m = 1500 kg Initial velocity, u = 0 m/s Final velocity, v = 20 m/s Time, t = 10 s (i) The acceleration of the car Step 1: Use the formula for acceleration: a = (v - u)/(t) Step 2: Substitute the given values: a = 20 m/s - 0 m/s10 s Step 3: Calculate the acceleration: a = 20 m/s10 s = 2 m/s^2 The acceleration of the car is 2 m/s^2. (ii) The net force acting on the car using Newton's second law (F = ma) Step 1: Use Newton's second law of motion: F = ma Step 2: Substitute the mass and the calculated acceleration: F = 1500 kg × 2 m/s^2 Step 3: Calculate the net force: F = 3000 N The net force acting on the car is 3000 N. Question 4 - 15 marks 4.a) Analyse the advantages and disadvantages of solar energy as a renewable energy source for Ghana. (10 marks) Advantages of Solar Energy for Ghana: • Abundant Resource: Ghana receives ample sunshine throughout the year, making solar energy a highly available and reliable renewable resource. • Environmental Benefits: Solar energy produces no greenhouse gas emissions during operation, contributing to cleaner air and mitigating climate change. • Energy Security: Reduces Ghana's reliance on imported fossil fuels and hydroelectric power, diversifying its energy mix and enhancing energy independence. • Decentralized Power: Solar panels can be installed in remote areas, providing electricity to communities not connected to the national grid, improving access to energy. • Job Creation: The solar industry creates jobs in manufacturing, installation, maintenance, and research and development. Disadvantages of Solar Energy for Ghana: • Intermittency: Solar power generation is dependent on sunlight, meaning it cannot produce electricity at night or during heavily cloudy periods, requiring energy storage solutions (batteries) or backup power. • High Initial Cost: The upfront investment for purchasing and installing solar panels and associated equipment (inverters, batteries) can be substantial. • Land Use: Large-scale solar farms require significant land area, which can compete with agriculture or other land uses. • Efficiency and Maintenance: The efficiency of solar panels can be affected by dust and high temperatures, requiring regular cleaning and maintenance. • Grid Integration Challenges: Integrating a large amount of intermittent solar power into the existing national grid can pose technical challenges for grid stability and management. 4.b) Describe the step-by-step process of installing solar panels in Ghana, highlighting the key considerations and safety protocols. (5 marks) Step-by-Step Installation Process: 1. Site Assessment and Design: Evaluate the location (e.g., roof or ground), assess sun exposure, shading, structural integrity, and determine system size based on energy needs. 2. Permitting and Approvals: Obtain necessary permits from local authorities and utility companies. 3. Mounting Structure Installation: Install the racking system (rails and mounts) securely onto the roof or ground, ensuring it can withstand local weather conditions. 4. Solar Panel Installation: Mount the solar panels onto the racking system, ensuring proper orientation and tilt angle for maximum sun exposure. 5. Electrical Wiring (DC): Connect the panels in series and/or parallel to form strings, running DC wiring from the panels to the inverter. 6. Inverter Installation: Install the inverter, which converts the DC electricity from the panels into usable AC electricity. 7. Electrical Wiring (AC) and Grid Connection: Connect the inverter to the main electrical panel of the building and, if applicable, to the national grid. 8. System Testing and Commissioning: Test the entire system to ensure it is functioning correctly and safely. Key Considerations and Safety Protocols: • Structural Integrity: Ensure the roof or ground structure can safely support the weight of the panels and mounting system. • Shading Analysis: Minimize shading from trees or other buildings to maximize energy production. • Electrical Safety: Always follow electrical codes, use insulated tools, ensure proper grounding, and implement lockout/tagout procedures during installation to prevent electrical shocks. • Fall Protection: Use safety harnesses, guardrails, and scaffolding when working at heights to prevent falls. • Weather Conditions: Avoid installation during adverse weather (e.g., heavy rain, strong winds). • Local Regulations: Adhere to all local building codes, electrical standards, and environmental regulations. 3 done, 2 left today. You're making progress.