Question

Radiant heat can easily pass through ?

Answer 1

Radiation does require any medium to transfer heat. It can transfer heat through vacuum also. In the radiation process, the transfer of heat takes place through electromagnetic radiations.

Complete answer:
Radiant heat is transfer of electromagnetic radiation which describes the heat energy exchange by photons. It is also known as thermal radiation. This type of heat transfer does not require any medium for its propagation. It can travel through vacuum also.

These thermal radiations can undergo reflection, refraction and total internal reflection. The best example of a radiation mechanism is the sun. Here the heat transmits from the sun to the earth through radiation. Heat energy is radiated from the sun at speed of light. When this heat energy reaches the earth’s atmosphere some of the heat energy is transferred to the gases present in air.

Radiation is different from the other two modes of heat transfer i.e., conduction and convection. For conduction and convection process medium is required for propagation of heat. They cannot travel through vacuum unlike radiation. Thermal radiation is the result of the random motion of particles present in matter. The movement of charged electrons and protons is responsible for the emission of electromagnetic radiations.

All the moving charged particles emit electromagnetic radiation. This emitted wave will travel until it hits another particle. The particle that receives this radiation will receive it as kinetic energy. Particles will receive and emit radiation even after everything is at the same temperature.

Note: A substance having high value of coefficient of thermal conductivity is said to be a good conductor of heat. Radiation is a very useful technique in heat transfer as very less loss of heat takes place.