Gas Fitter Practice Test

Which heat is removed or added to cause a change in state without change in temperature?

1. Sensible heat

2. Radiant heat

3. Latent heat

4. Super heat

The correct answer is: Latent heat

The concept of latent heat refers to the heat absorbed or released during a phase change of a substance, such as melting, freezing, boiling, or condensing, without a change in temperature. For example, when ice turns into water, it absorbs heat (latent heat of fusion) while remaining at 0°C until all ice has converted to water. Similarly, when water vaporizes into steam, it absorbs latent heat of vaporization without raising its temperature during the process. This characteristic distinguishes latent heat from other forms of heat exchange. Sensible heat involves changes in temperature of a substance without a change of state, meaning that when heat is added or removed, the temperature changes but the state (solid, liquid, gas) remains the same. Radiant heat pertains to heat transfer through electromagnetic waves, which can also cause temperature changes rather than a change in state. Super heat is a specific term referring to the heating of a vapor beyond its boiling point at a given pressure, also resulting in temperature change rather than a phase transition. Understanding latent heat is crucial for gas fitters, as it relates to the principles of heating and cooling systems that involve changing states, such as in refrigeration and air conditioning systems.