Heat energy is transferred by conduction whenever molecules _ while radiation is the only form of heat transfer that can
The Correct Answer and Explanation is:
Heat energy is transferred by conduction whenever molecules collide with one another. Conduction occurs in solids, liquids, and gases, but it is most effective in solids because the particles are closely packed together. When a region of a substance is heated, the molecules in that region gain energy and vibrate more vigorously. As they collide with neighboring molecules, they transfer some of their energy to them, causing a chain reaction that passes heat through the material. This process continues as long as there is a temperature difference between two regions of the material. An example of conduction can be seen when a metal spoon is placed in a hot liquid; the heat travels from the hot liquid to the spoon through molecular collisions, making the spoon warm.
Radiation, on the other hand, is the only form of heat transfer that can occur through a vacuum. Unlike conduction and convection, which require a medium (solid, liquid, or gas) to transfer heat, radiation involves the transfer of energy in the form of electromagnetic waves, such as infrared radiation. These waves can travel through empty space, as demonstrated by the warmth we feel from the Sun despite the vacuum of space. All objects emit radiation depending on their temperature; hotter objects emit more radiation, which can be absorbed by cooler objects, leading to a transfer of heat energy. For instance, when you stand near a campfire, you can feel the heat even though there is no direct contact with the fire or air. This is radiation in action.
In summary, conduction transfers heat through direct molecular collisions, while radiation can transfer heat without the need for a medium, even across the vacuum of space.
