The vacuum in a thermos flask helps to reduce heat transfer by?

Gbite

5 years ago

can someone explain

notmoses

1 year ago

A thermos flask is designed to minimize heat transfer and keep liquids hot or cold for a long time. It does this using:
Vacuum Layer – The space between the inner and outer walls is a vacuum, which prevents heat transfer by conduction and convection because:
Conduction requires particles to transfer heat, but a vacuum has no particles.
Convection requires a fluid (liquid or gas) to circulate heat, but a vacuum prevents this.
Silvered Inner Surface – Reduces radiation by reflecting heat back into the liquid.
Why not the other options?
A. Convection and Radiation ❌ – The vacuum prevents convection, but it does not completely stop radiation.
C. Conduction and Radiation ❌ – The vacuum stops conduction, but radiation is reduced by the silvered surface, not the vacuum itself.
D. Radiation only ❌ – The vacuum does not only stop radiation; it primarily prevents conduction and convection.
Thus, the best choice is B. Convection and Conduction!

Dave333

4 years ago

Note:since both cannot travel throughout a vacuum unlike radiation