Question

Air is a bad conductor of heat or partly conducts heat, still, the vacuum is to be placed between the walls of the thermos flask because

• A. it is difficult to fill the air between the walls of thermos flask
• B. due to more pressure of air, the thermos can get crack
• C. by convection, heat can flow through air
• D. on filling the air, there is no advantage

Answer 1

Answer: (C)

No flow of heat by convection in vacuum. As convection requires medium particle to propogate.