The mode of transference of heat which does not require any material medium is

Step 1: Analyze the question The question asks which method of heat transfer can happen without a material medium. That means it must work even in a vacuum, such as the empty space between the Sun and the Earth.

Step 2: Review the modes of heat transfer

• Conduction (A): Heat passes from particle to particle through direct contact, mostly in solids. It needs a material medium, for example a metal spoon heated at one end.
• Convection (B): Heat is carried by the movement of fluids (liquids and gases). It also needs a medium, for example boiling water or sea breezes.
• Evaporation (C): This is a change of state from liquid to vapour at the surface of a liquid. It is a cooling process, not a mode of heat transfer, and it needs a liquid.
• Radiation (D): Heat is transferred as electromagnetic waves (infrared). These waves travel through a vacuum, so no medium is needed. This is how the Sun's heat reaches us through space.
• Transmission (E): This is not a standard mode of heat transfer, and it is too vague to be correct here.

Step 3: Identify the answer Only radiation needs no material medium, so the answer is D.

Exam tip: Remember the phrase "Radiation = Rays = Region of empty space." If a question mentions a vacuum, the Sun, or "no medium," think radiation. Conduction and convection always need matter: solids for conduction, fluids for convection.