An object and a source of heat are placed in two different experimental setups. Setup 1: Vacuum is present between the object and the source in a confined tube. Setup 2: Metallic fibres are stuffed into the space between the source and object, in a confined tube. To achieve successful heating of the object, which modes of heat transfer must occur in the two setups?
Answers
To achieve successful heating of the object, the modes of heat transfer that must occur in the two setups are explained below:
Setup 1 - Radiation
Setup 2 - Conduction
Setup1: Vacuum is present between the object and the source in a confined tube.
As given, no medium is present between the object and the source in the confined tube. In this case, conduction or convection cannot occur as both require a medium to transfer heat.
Only radiation is the mode of heat transfer that can occur without any medium. Energy is emitted from the source in the form of photons or electromagnetic waves in case of radiation. This can travel through vacuum and reach the object.
Setup 2: Metallic fibres are stuffed into the space between the source and object, in a confined tube.
As given, metallic fibres are present in between the source and object. Metals transfer heat by means of conduction. The closely-packed particles of metal absorb the heat and transfer the energy to the neighbouring particles.