Which energy does a thermos flask use?

6th Std. – ENGLISH                                                                                      YEAR OF EXAMINATION : 2014 DR. HOMI BHABHA BAL VAIDNYANIK COMPETITIVE EXAMINATION

Q. 2. Which of the following is not working on electric energy?
. A. Mobile phone         B.Thermos flask      C. Torch         D. Laptop

Answer : (B) Thermos Flask

Explanation

Vacuum flasks are used domestically to keep beverages hot or cold for extended periods of time and for many purposes in industry.

Thermos is a storage vessel that greatly lengthens the time over which its contents remain hotter or cooler than the flask's surroundings.

Invented by Sir James Dewar in 1892

The vacuum flask consists of two flasks, placed one within the other and joined at the neck. The gap between the two flasks is partially evacuated of air, creating a near-vacuum which prevents heat transfer by conduction or convection.

Thus a thermos flask is not working on electrical energy unlike mobile phone, torch and laptop.