''Heat cannot by itself flow from a body at lower temperature to a body at higher temperature'' is a statement or consequence of :

Heat and Thermodynamics PYQ — JEE Main 2003 · Shift 0 · Q154 with Solution

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Correct answer: A

The statement given is:

$\text{"Heat cannot by itself flow from a body at lower temperature to a body at higher temperature."}$
This is the Clausius statement of the second law of thermodynamics.
Meaning:
- Heat flows naturally from a hotter body to a colder body.
- For heat to go from colder to hotter, external work is required (as in a refrigerator).
Now check the options:
- A: second law of thermodynamics — Correct, because the statement is directly from the second law.
- B: conservation of momentum — Not related to heat flow.
- C: conservation of mass — Not related to this thermodynamic statement.
- D: first law of thermodynamics — The first law is about conservation of energy, not the direction of heat flow.
Therefore, the correct answer is:

$\boxed{\text{A}}$

View written solutionFree

Correct answer: A

The statement given is:

$\text{"Heat cannot by itself flow from a body at lower temperature to a body at higher temperature."}$
This is the Clausius statement of the second law of thermodynamics.
Meaning:
- Heat flows naturally from a hotter body to a colder body.
- For heat to go from colder to hotter, external work is required (as in a refrigerator).
Now check the options:
- A: second law of thermodynamics — Correct, because the statement is directly from the second law.
- B: conservation of momentum — Not related to heat flow.
- C: conservation of mass — Not related to this thermodynamic statement.
- D: first law of thermodynamics — The first law is about conservation of energy, not the direction of heat flow.
Therefore, the correct answer is:

$\boxed{\text{A}}$