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Heat energy can be transferred by conduction, convection and radiation - Leaving Cert Physics - Question c - 2018
Question c
Heat energy can be transferred by conduction, convection and radiation. Distinguish between the three methods of heat transfer.
Worked Solution & Example Answer:Heat energy can be transferred by conduction, convection and radiation - Leaving Cert Physics - Question c - 2018
Step 1
Conduction: No net movement of medium
Answer
Conduction is the process of heat transfer through direct contact between materials. In conduction, heat is transferred from one particle to another without any overall movement of the medium. This occurs in solids, where particles vibrate and pass their kinetic energy to adjacent particles. A common example is heating one end of a metal rod, causing the heat to travel to the other end.
Step 2
Convection: Circulation of a fluid
Answer
Convection involves the transfer of heat by the movement of fluids (liquids or gases). As a fluid is heated, it becomes less dense and rises, while cooler, denser fluid sinks. This creates a circulation pattern that promotes heat transfer. An example of convection is boiling water, where hot water rises to the surface and cooler water moves down.
Step 3
Radiation: Electromagnetic / photons / through a vacuum
Answer
Radiation is the transfer of heat in the form of electromagnetic waves, allowing heat to be transferred through a vacuum. Unlike conduction and convection, it does not require a medium to travel through. The warmth felt from sunlight or a heat lamp is an example of radiation, where heat energy is emitted as photons and can travel through space.