MCQ Detailed View

The triple point of water is a very important concept in physics and thermodynamics. It is defined as the specific condition of temperature and pressure at which water can exist in all three states of matter — solid (ice), liquid (water), and gas (water vapor) — at the same time in equilibrium.

The triple point of water occurs at a temperature of 273.16 K (0.01 °C) and a pressure of 611.657 pascals. This is a unique point because under these exact conditions, ice, liquid water, and vapor can coexist without any of the phases disappearing. If either the temperature or pressure changes slightly, one of the phases will vanish and the system will no longer remain in equilibrium.

This point is extremely important in thermodynamics because it is used as a fundamental reference for defining temperature scales. In fact, the Kelvin scale of temperature is based on the triple point of water. The value 273.16 K is chosen as the reference point because it is highly reproducible in experiments and provides an exact standard for scientific measurements.

For students, it is important to understand that the triple point is not just a random value. It represents the physical reality of phase equilibrium. At normal atmospheric pressure, water boils at 100 °C and freezes at 0 °C, but at the special pressure of 611 pascals, these three states can appear together at 0.01 °C.

The concept of the triple point is applied in climate science, physics experiments, calibration of thermometers, and even in defining international measurement standards.

Thus, the correct answer is 273.16 K, which is the scientifically defined triple point of water.