TS EAMCET202014 Sep 2020Morning ShiftPhysicsThermal Properties of MatterActual
Assertion A thermos bottle consists of a double walled glass vessel with the space between the two walls evacuated, so that the heat transfer between the contents of the bottle and outside is minimised. Reason The vacuum between the two walls inhibits the heat transfer by radiation mechanism. Which of the following is correct?
Options
- AAssertion is true, Reason is true and Reason is the correct explanation for Assertion.
- BAssertion is true, Reason is true but Reason is not the correct explanation for Assertion.
- CAssertion is true but Reason is false.
- DAssertion is false but Reason is true.
Correct answer
C. Assertion is true but Reason is false.
Step-by-step solution
The space between the two walls of a thermos bottle is evacuated, so that the heat transfer due to conduction and convection can be prevented. But heat can travel through vacuum. So this evacuated space cannot prevent the heat transfer due to radiation. Hence, Assertion is true, but Reason is false.