Question

Why do we use vaccum flask to keep hot water or tea for a longer time​

Answer 1

Answer:

Answer is

Explanation:

Sorry I don't know

Answer 2

Answer:

The vacuum prevents conduction. The tight stopper prevents air from entering or leaving the flask, so convection isn't possible either. ... There's virtually no way heat can escape from a vacuum flask and a hot drink stored inside will stay steaming hot for several hours. Flasks also work for cold drinks.