According to the video, we feel the heat from the radiator mainly by __. *
A conduction
B radiation
C convection
The correct answer and explanation is :
Correct Answer: B. Radiation
We feel the heat from a radiator mainly by radiation.
Explanation (Approx. 300 words):
Heat can be transferred in three primary ways: conduction, convection, and radiation. When it comes to how we feel warmth from a radiator across a room, radiation is the main mechanism.
Radiation involves the transfer of heat through electromagnetic waves, particularly infrared radiation. Unlike conduction and convection, radiation does not need a medium like air or metal to travel. This means that thermal radiation can travel through a vacuum (like from the Sun to the Earth) and also through air. When a radiator heats up, it emits infrared radiation. These invisible rays travel in straight lines and are absorbed by nearby objects—including your skin—making you feel warm.
Conduction happens when heat is transferred through direct contact. For example, if you touch the surface of a hot radiator, the heat is transferred to your hand by conduction. However, if you’re just standing near the radiator without touching it, conduction isn’t involved in how you feel the warmth.
Convection is the transfer of heat through the movement of fluids or gases. In a room, the air near the radiator warms up, becomes less dense, and rises. Cooler air then replaces it, creating a convection current. While this process helps heat the room overall, convection does not account for the immediate sensation of warmth on your skin when you’re standing near the radiator. That sensation comes from the infrared radiation striking and being absorbed by your body.
Therefore, although convection helps distribute heat in a room and conduction plays a role when touching the radiator, radiation is the primary way we feel heat directly from a radiator at a distance.