Question

1 . In the given picture of the thermos flask what do labelling A, B, C and D represent?
2 . Explain how the part labelled as ‘A’ is helpful in preventing transfer of heat in the
thermos flask?

Answer 1

Answer:

1. A - Stopper

B - Pollished Walls

C - Glass or Metal Bottle

D - No air

Explanation:

2. Stopper is helpful in preventing transfer of heat in the thermos flask because:

(a) The stopper made of an insulator such as cork or plastic closes the mouth of the flask. This feature minimise loss of heat due to conduction.

(b) It also prevents the heat loss by convection because it is tightly sealed. And the inner reflecting layer prevents the heat loss by radiation.