 # According to the law of calorimetry, which of the given relation is true? (A) Heat gained = Heat lost (B) There is no change in heat (C) There is only heat gain (D) There is only heat loss

Answer: (A) Heat gained = Heat lost

### What is calorimetry?

The science of measuring the changes in the state variables of a body in order to calculate the heat transfer associated with changes of its states such as physical changes or phase transitions under specific conditions is known as calorimetry.

### Law of calorimetry

According to the law of calorimetry, Heat gained = Heat lost

According to the law of calorimetry or principle of calorimetry states that if there is no heat loss in the surrounding, then the heat lost by the body is equal to the heat gained by the body.

### Explanation

When two bodies of different temperatures (preferably a solid and a liquid) are placed in physical contact with each other, the heat is transferred from the body with higher temperature to the body with lower temperature until thermal equilibrium is attained between them. The body at higher temperature releases heat while the body at lower temperature absorbs heat. The principle of calorimetry indicates the law of conservation energy, i.e. the total heat lost by the hot body is equal to the total heat gained by the cold body.

Heat Lost = Heat Gained

### Formula

Following is the formula which is used for calculating the heat transfer in a system:
q = mcΔt
Where,

• q is the measure of heat transfer
• m is the mass of the body
• c is the specific heat of the body
• Δt is the change in temperature (7) (4)