Direct transfer of energy between two objects in physical contact is called which?

Direct transfer of energy between two objects in physical contact is called which?

• A. Conduction
• B. Convection
• C. Radiation
• D. Cryotherapy

Answer: (A)

Direct transfer of energy through physical contact happens by conduction. When two objects touch, energy moves from the warmer one to the cooler one at the interface through molecular interactions, and the rate depends on the temperature difference, the contact area, and how well the materials conduct heat. For example, an ice pack drawing heat from the skin or a hot pan warming your hand are conduction events. Convection, in contrast, transfers energy via movement of a fluid or gas, like warm air circulating or boiling water. Radiation transfers energy through electromagnetic waves and can heat you without any contact. Cryotherapy is a treatment method that often uses conduction to cool tissue, but the mechanism described is conduction itself, not the therapy category.

Direct transfer of energy through physical contact happens by conduction. When two objects touch, energy moves from the warmer one to the cooler one at the interface through molecular interactions, and the rate depends on the temperature difference, the contact area, and how well the materials conduct heat. For example, an ice pack drawing heat from the skin or a hot pan warming your hand are conduction events.

Convection, in contrast, transfers energy via movement of a fluid or gas, like warm air circulating or boiling water. Radiation transfers energy through electromagnetic waves and can heat you without any contact. Cryotherapy is a treatment method that often uses conduction to cool tissue, but the mechanism described is conduction itself, not the therapy category.