Question

Assertion: According to the principle of calorimetry: Heat gained by a cold body = Heat lost by a hot body.

Reason: Heat is a form of energy, so according to the law of conservation of energy, the energy cannot be created or destroyed and its sum total remains the same.

• A. Both ‘A’ and ‘R’ are correct and ‘R’ is the correct explanation of ‘A’.
• B. Both ‘A’ and ‘R’ are correct, but ‘R’ is not the correct explanation of ‘A’.
• C. ‘A’ is correct, but ‘R’ is incorrect
• D. ‘A’ is incorrect, but ‘R’ is correct

Answer 1

The correct option is A

Both ‘A’ and ‘R’ are correct and ‘R’ is the correct explanation of ‘A’.

The explanation for the assertion:

1. Heat flows from a hot body to the surrounding cool bodies until all the bodies attain thermal equilibrium.
2. So, the heat lost by a hot body = the heat gained by the cold body.

The explanation for the reason:

1. The whole energy in this universe is conserved.
2. It can neither be created nor destroyed.
3. Energy flows from one body to another.
4. Heat is a form of energy that flows from the hot bodies to the cold bodies.

Hence, the answer is (A) Both ‘A’ and ‘R’ are correct and ‘R’ is the correct explanation of ‘A’.