What is sensible heat in the context of heating water?

• A. Heat that changes water into ice
• B. Heat that causes temperature to rise to boiling point
• C. Heat that evaporates water without temperature change
• D. Heat that maintains water at a constant temperature

Answer: (B)

Sensible heat refers to the heat exchanged that results in a change in temperature of a substance without changing its phase. In the context of heating water, this means that when you apply heat to water, the temperature increases until it reaches its boiling point.

When water is heated, the thermal energy from the heat source is absorbed and leads to an increase in the kinetic energy of the water molecules, which raises the temperature. The specific heat capacity of water indicates how much heat energy is needed to increase the temperature of a given amount of water by one degree Celsius. Option B highlights this phenomenon perfectly, as it focuses on the heat applied that causes the temperature to rise up to the point where water starts to boil.

The other options describe different processes. The conversion of water into ice refers to the heat removal that occurs during freezing, which is related to latent heat, not sensible heat. Evaporation without temperature change also pertains to latent heat, as the water can absorb heat while remaining at a constant temperature during the phase change from liquid to vapor. Finally, maintaining water at a constant temperature does not involve adding or removing sensible heat, as it typically suggests a balance where heat input equals heat loss, thus no net change in temperature occurs in that scenario.