Question

Amount of heat required to raise the temperature of a body through \(1 \mathrm{k}\) is called its (A) water equivalent (B) Thermal capacity (C) entropy (D) specific heat

Short answer

The correct term is (B) Thermal capacity, as it refers to the amount of heat required to raise the temperature of a body through 1 Kelvin.

Step-by-step solution

Define water equivalent

Water equivalent is the amount of water that can be heated with the same amount of heat as the given body and exhibit the same change in temperature.

Define thermal capacity

Thermal capacity is the amount of heat required to raise the temperature of a body by 1 Kelvin. It is equal to the mass of the body times its specific heat capacity.

Define entropy

Entropy is a measure of the disorder of a system, or the amount of energy unavailable to do work.

Define specific heat

Specific heat is the amount of heat required to raise the temperature of a unit mass of a substance by 1 Kelvin.

Determine the correct term

Based on the definitions, the correct term is (B) Thermal capacity, which is the amount of heat required to raise the temperature of a body through 1 Kelvin.

Key concepts

Specific Heat

Specific heat is a vital concept in understanding how different substances respond to heat. It refers to the amount of heat required to raise the temperature of 1 kilogram of a substance by 1 degree Celsius (or 1 Kelvin). This means each substance has its unique specific heat, influencing how it absorbs or loses heat.
What makes specific heat fascinating is that it explains why some materials feel warmer or cooler to the touch. For example, water has a high specific heat, meaning it can absorb a lot of heat without a significant change in temperature. Metals, on the other hand, tend to have low specific heat values.
Knowing the specific heat of a material is essential in various fields like cooking, meteorology, and engineering, as it helps in predicting how much energy or heat a substance can store and how quickly it will heat or cool. These are crucial factors to consider when designing systems that involve heating or cooling processes.

Water Equivalent

The concept of water equivalent is particularly useful in calorimetry, a branch of science focused on measuring the amount of heat absorbed or released during chemical reactions or changes in state. Water equivalent is an imaginary explanation, helping us understand how a given amount of heat affects different materials.
It is defined as the mass of water that would experience the same temperature change when the same quantity of heat is applied. Essentially, it's a way to compare the heat capacity of a material to that of water.
Here's why this concept is handy:

• Comparative Measure: It lets us translate heat capacity into terms easily understandable by relating to water.
• Simplification: Provides a simpler way to assess and quantify energy transfers when dealing with diverse materials in experiments.

This approach assists students and scientists alike, offering a clearer picture of thermal properties and facilitating easier calculations in thermal experiments.

Entropy

Entropy, though a bit more abstract than other thermal properties, is a fundamental part of understanding thermodynamics. It's often described as a measure of disorder within a system, indicating how energy within a system is distributed and how much of that energy is available for performing work.
When we say a system has high entropy, it implies that its energy is spread out and less organized, and thus less energy is available to do work. Low entropy means more organized energy able to perform more efficient work. Entropy can be seen as a measure of uncertainty or randomness in the energy distribution of molecules within a system.
This concept becomes crucial when:

• Understanding Thermodynamics: It plays a key role in explaining why certain processes are irreversible and how energy efficiency affects systems.
• Predicting States: Helps in determining the likelihood of a system's configuration and its natural evolution over time.

Ultimately, entropy links directly to the second law of thermodynamics, emphasizing that the total entropy of an isolated system can never decrease over time, making it an essential principle in physics and chemistry.