Question 1: Thermal energy store refers to the energy stored within a substance due to the random motion of its particles. When a substance heats up, its particles gain kinetic energy, increasing its thermal energy store. Heat transfer occurs via conduction, convection, and radiation.

Answer: Thermal energy store is the energy stored in a substance due to particle motion, increasing as temperature rises.

Question 2: List the three main methods of heat transfer involved in changing the thermal energy store of a substance.

Answer: Conduction, convection, radiation.

Question 1: Explain how conduction occurs in a metal rod heated at one end.

Answer: Conduction occurs when particles at the heated end vibrate more vigorously, transferring kinetic energy to neighbouring particles through direct contact, causing heat to flow along the rod.

Question 2: Describe how convection transfers heat in fluids such as air or water.

Answer: Convection involves the movement of fluid particles; warm, less dense regions rise, while cooler, denser regions sink, creating a circulation that transfers heat.

Question 3: What role does radiation play in heat transfer, and why can it occur even in a vacuum?

Answer: Radiation transfers heat via electromagnetic waves, which do not require a medium, so it can occur through a vacuum like space.

Question 1: A 2 kg aluminium block is heated so that its temperature increases by 50°C. Given the specific heat capacity of aluminium is 900 J/kg°C, calculate the thermal energy transferred to the block.

Answer: 900 J/kg°C × 2 kg × 50°C = 90,000 J

Question 2: If the thermal energy transferred to an object is 120,000 J and its specific heat capacity is 600 J/kg°C, what is the temperature change of a 4 kg substance?

Answer: ΔT = 120,000 J / (600 J/kg°C × 4 kg) = 50°C

Question 1: Describe a simple experiment to demonstrate heat transfer by conduction using metals. Include the variables you would control and safety precautions.

Answer: Use metal rods of different materials heated at one end and measure temperature change at the other end over time. Control variables include rod length, material, and initial temperature. Safety precautions involve handling hot equipment with tongs and wearing safety goggles.

Question 1: A hot water cylinder is insulated to reduce heat loss. Explain how insulation affects the thermal energy store of the water and the overall efficiency of heating systems.

Answer: Insulation reduces heat transfer from the water, maintaining its thermal energy store longer and increasing efficiency by requiring less energy to keep the water hot.

Question 2: In industries such as cooking or manufacturing, how is knowledge of thermal energy stores utilised to improve energy efficiency and safety?

Answer: Industries use insulation to minimise heat loss, sensors to monitor temperature changes, and safety protocols to prevent burns or overheating. Understanding thermal energy stores helps optimise energy consumption and ensures safe operation of equipment.