A vacuum flask is used to keep liquids hot or cold for long periods
PHYSICS · Subjective · GCSE · Physics · Energy · Energy
Problem
A vacuum flask is used to keep liquids hot or cold for long periods.
(a) Describe the essential constructional features of a typical vacuum flask.
(b) Explain how each of the following features helps in reducing heat loss by conduction:
(i) the double-walled glass vessel, and
(ii) the vacuum between the walls.
(c) Explain how the flask minimises heat loss by convection.
(d) The inner glass surfaces are silvered. Explain how this treatment reduces heat loss by radiation.