Question

Vacuum in a vacuum flask prevents heat transfer through process of-

• A. Conduction only
• B. Conduction and Convection
• C. Convection only
• D. Radiation only

Answer 1

The correct option is B Conduction and Convection

Vacuum in a vacuum flask prevents heat transfer through process of conduction and convection.

It is so because, in conduction there needs a direct contact for transfer of heat and there is vaccum between two layers, so conduction can't transfer heat in this case. And in convection, heat is transferred by molecular motion in fluid (liquid or gas). But due to vaccum's presence between two layers, molecular motion is not possible So convection is also impossible for this case.