iGCSE Physics (0625) 2.3.4 Consequences of energy transfer-Exam Style Questions- New Syllabus
▶️ Answer/Explanation
Detailed solution:
Thermal energy transfer between two solids in direct physical contact occurs via conduction.
The prompt states there is “no air gap” between the hotplate and the metal pan, ensuring direct contact.
In the metal hotplate, heat is transferred to the pan’s base as vibrating particles collide and transfer kinetic energy.
Convection (Options B and D) requires a fluid medium like a liquid or gas to circulate, which is not the case here.
Radiation (Option A) occurs through electromagnetic waves and does not require contact, but it is not the primary mode described.
Therefore, Statement C correctly identifies conduction as the method of energy transfer for the metal hotplate.
▶️ Answer/Explanation
Detailed solution:
Thermal conduction is the process where heat is transferred through a solid material via atomic vibrations and electron movement. Metals are excellent conductors, while wood is a poor conductor (a thermal insulator). By using wood for the handle, the rate of thermal energy transfer from the hot pan to the user’s hand is significantly lowered. This prevents the handle from reaching high temperatures, ensuring safety during cooking. Since heat travels through the solid material of the handle, the primary mechanism being addressed is conduction rather than convection, which occurs in fluids. Therefore, wood is chosen specifically to reduce thermal energy transfer by conduction.