Question

Rate of radiation of heat from a body is the highest of its surface is

Answer 1

Radiation of heat from a body is at its maximum, when the body surface is exposed. If the body surface is covered, radiation of heat is drastically reduced, depending upon the material used as cover.

Thermal radiation is electromagnetic radiation and all matter with temperature greater than zero emits heat. Heat energy moves as energy waves, from a hot object to cooler objects.  

Heat transmitted in three ways – by radiation, conduction and convection.