Question

According to the law of calorimetry, which of the given relation is true?

• A. $Heatgained=Heatlost$
• B. There is no change in heat
• C. There is only heat gain
• D. There is only heat loss

Answer 1

The correct option is A

$Heatgained=Heatlost$

Correct Option: Option A

1. Law of calorimetry is the law that indicates conservation of energy.
2. According to this law, “When there is no heat loss in the surroundings, then the heat lost by a body is equal to the heat gained by another body kept in contact with it.” Mathematically, it can be expressed as $Heatgained=Heatlost$.
3. When 2 bodies with different temperatures are kept in contact, the heat flows from the hotter body to the colder body, until they achieve thermal equilibrium, that is the temperature of both bodies are same.
4. The heat transfer in a system is given by $Q=mc∆t$, where $m$ is the mass of the body, $c$ is the specific heat of the body and $∆t$ is the change in temperature.

An illustration of the Law of Calorimetry between a can and ice cube (assuming no heat lost or gained in surroundings)

Incorrect Options:

Option B

According to this law, there is no change in heat of the entire system, but the heat of the two bodies change, one of the body losses heat while the other gains. Hence, this option is incorrect.

Option C

The heat of the two bodies change, one of the body losses heat while the other gains. Hence, this option is incorrect.

Option D

The heat of the two bodies change, one of the body losses heat while the other gains. Hence, this option is incorrect.

Hence, the correct option is (A).