Which process results in a change without a measurable temperature change?

• A. Sensible heat transfer
• B. Latent heat transfer
• C. Convection heat transfer
• D. Conduction heat transfer

Answer: (B)

The process that results in a change without a measurable temperature change is latent heat transfer. This phenomenon occurs during phase changes of a substance, such as when ice melts into water or when water evaporates into steam. During these transitions, the energy added or removed from the substance goes into breaking or forming molecular bonds rather than increasing the temperature.

For instance, when ice absorbs heat, it does not increase in temperature until it has completely melted into water. Likewise, when water evaporates, it absorbs heat without an increase in temperature until the phase change is complete. This concept is critical in understanding thermodynamic processes, particularly in refrigeration and air conditioning systems where moisture removal (dehumidification) often involves latent heat.

In contrast, sensible heat transfer is associated with a change in temperature in a substance, while convection and conduction heat transfer are methods of heat transfer that can also result in temperature changes in a material. These processes do not involve phase changes and, therefore, do not fit the criteria of causing changes without a measurable temperature change.