CBSE Class 11-science Answered
The coil or radiator in room heaters transfer heat to the nearby air. The air near the radiator on heating expands and its density decreases and it rises up. As the hot air rises up it pushes down the cold air which further gets in contact with heater and gets heated. This process goes on and makes the room warm. As the hot air touches the roof or walls of the room, it loses its heat by collisions and cools down.
The Efficiency of the radiator of room heaters can be improved by placing a shiny metal foil behind it.