The quantity of heat needed to raise the temperature of a body by 1K is the body's

Analysis

The question asks for the definition of the physical quantity that describes the amount of heat energy required to increase the temperature of a specific object (a body) by 1 Kelvin (or 1 degree Celsius).

Concept Explanation

To understand this, we must distinguish between Heat Capacity and Specific Heat Capacity:

1. Heat Capacity ($C$): This is the quantity of heat required to raise the temperature of a whole body (regardless of its mass) by 1K or 1°C. Its unit is $J/K$. • Formula: $Q = C \Delta\theta$ (where $C$ is heat capacity).
2. Specific Heat Capacity ($c$): This is the quantity of heat required to raise the temperature of a unit mass (usually 1kg) of a substance by 1K or 1°C. Its unit is $J/kg \cdot K$. • Formula: $Q = mc \Delta\theta$ (where $c$ is specific heat capacity).

Since the question refers to "a body" (implying the object as a whole) rather than a "unit mass," we are referring to the heat capacity.

Step-by-Step Solution

• Step 1: Identify the variables. We are looking for the ratio of heat energy ($Q$) to the change in temperature ($\Delta\theta$).
• Step 2: Apply the definition. The definition of heat capacity is $C = \frac{Q}{\Delta\theta}$.
• Step 3: Evaluate the options. • A (Heat capacity): Matches the definition perfectly. • B (Internal energy): This is the total kinetic and potential energy of the molecules within the body, not the energy required to change its temperature. • C (Specific heat capacity): Requires the mass of the body to be specified (1kg). • D (Latent heat of fusion): This is the heat required to change the state of a substance from solid to liquid at a constant temperature, not to raise the temperature.

Conclusion

The correct term for the heat required to raise the temperature of a body by 1K is its heat capacity.