Question

A thermos flask maintains temperature of objects. It

• A. containing some kind of heating element to keep hot things hot.
• B. containing some kind of heating element to keep cold things cold.
• C. keeps hot things hot by not allowing heat to escape.
• D. All of the above

Answer 1

The correct option is C keeps hot things hot by not allowing heat to escape.

A thermos flask maintains temperature of objects. It keeps hot things hot by not allowing heat to escape.

Thermos flask doesn't allow heat to escape from it via any mode of heat transfer i.e. conduction, convection, radiation. It does so by silver coating or polishing inner surface thin walls and vacuum between two walls.