Kelvin Scale: History, Formula & Solved Examples

Ans. To convert from Kelvin to Celsius, we need to subtract 273.15 from the Kelvin temperature.

Given: Temperature in Kelvin = 450 Kelvin

Conversion formula: Celsius = Kelvin - 273.15

Substituting the given value: Celsius = 450 - 273.15

Calculating: Celsius = 176.85

Therefore, the substance with a temperature of 450 Kelvin is equivalent to 176.85 degrees Celsius.

Ans. To convert Kelvin to Celsius, we subtract 273.15 from the given temperature in Kelvin.

Temperature in Celsius = 300 K - 273.15 = 26.85 °C

To convert Celsius to Fahrenheit, we use the formula (Celsius × 9/5) + 32.

Temperature in Fahrenheit = (26.85 × 9/5) + 32 = 80.33 °F

Therefore, the temperature of the substance is 26.85 °C and 80.33 °F on the Celsius and Fahrenheit scales, respectively, when measured at 300 K on the Kelvin scale.

Ans. Absolute zero is the lowest possible temperature on the Kelvin scale, which is defined as 0 Kelvin (0 K).

• It is significant because it represents the complete absence of thermal energy in a substance. 
• At absolute zero, all molecular motion ceases, and substances reach their lowest possible energy state. 
• This makes the Kelvin scale ideal for scientific and thermodynamic calculations because it provides a temperature reference point where all substances have zero thermal energy. 
• It allows for more precise and consistent measurements and calculations in various scientific fields, such as physics and chemistry.

Ans. The Kelvin scale, Celsius scale, and Fahrenheit scale are three different temperature scales. 

• The Kelvin scale has an absolute zero point at 0 Kelvin, which represents the complete absence of molecular motion. In contrast, Celsius and Fahrenheit scales have their zero points set arbitrarily.
• Kelvin is the base unit of temperature in the International System of Units (SI), whereas Celsius and Fahrenheit are derived units.
• The Kelvin scale has the same magnitude as the Celsius scale, with the only difference being the offset of the zero point. On the other hand, the Fahrenheit scale has a different magnitude and interval size.
• The Kelvin scale is an absolute temperature scale used in scientific and engineering applications, while the Celsius and Fahrenheit scales are more commonly used in everyday temperature measurements.
• The Kelvin scale does not have negative values, as it measures temperature relative to absolute zero. In contrast, both Celsius and Fahrenheit scales have negative values.
• The Kelvin scale is considered more precise for scientific purposes, as it eliminates the need for negative values and provides a linear relationship between temperature and thermal energy.

Ans. The formula for converting Celsius to Kelvin is:

Kelvin = Celsius + 273.15

To convert Kelvin to Celsius, the formula is: Celsius = Kelvin - 273.15

These formulas involve adding or subtracting 273.15, which is the difference in the scales' zero points. By applying these formulas, you can easily convert temperatures between the Celsius and Kelvin scales.

Ans. Water freezes at 273.15 Kelvin and boils at 373.15 Kelvin on the Kelvin scale. These values correspond to the temperatures at which water undergoes a phase change from solid to liquid (freezing) and from liquid to gas (boiling) at standard atmospheric pressure.

Ans. The Kelvin scale is closely related to the concept of molecular motion. As the temperature increases on the Kelvin scale, the average kinetic energy of the molecules in a substance also increases. This means that the molecules move faster and with greater energy. At absolute zero, which is 0 Kelvin, molecular motion theoretically ceases, as the molecules have the least amount of energy. As the temperature increases above absolute zero on the Kelvin scale, molecular motion becomes more pronounced, leading to various physical and chemical phenomena observed at higher temperatures.

Ans. The primary temperature unit used in the Kelvin scale is the Kelvin (K). It is an absolute temperature scale where zero Kelvin (0 K) corresponds to absolute zero, the point at which molecular motion theoretically ceases. The Kelvin scale is based on the same interval as the Celsius scale, with the difference being that the Kelvin scale starts from absolute zero, while the Celsius scale starts from the freezing point of water. The Kelvin scale does not use degrees (°) symbol, unlike the Celsius and Fahrenheit scales.

Ans. While the Kelvin scale is widely used and has many advantages, there are a few limitations and drawbacks to consider:

Limited familiarity: The Kelvin scale is less commonly used in everyday life compared to the Celsius and Fahrenheit scales, which can make it less intuitive for general temperature references.

Inconvenience for everyday use: The Kelvin scale does not use negative values, which means that temperature values below absolute zero are represented as positive values. This can be confusing and inconvenient for everyday temperature measurements.

Limited relevance to human experience: The Kelvin scale is primarily used in scientific and technical contexts, such as in physics and engineering. For everyday human experiences and weather-related discussions, the Celsius and Fahrenheit scales are more relatable.

Lack of granularity: The Kelvin scale has a smaller unit of measurement compared to the Celsius and Fahrenheit scales, which can make it less suitable for measuring small temperature variations or for applications that require precise temperature control.

Limited cultural adoption: The Kelvin scale is not as widely adopted in some regions or cultures, where the Celsius or Fahrenheit scales may be more commonly used, leading to potential challenges in communication and comprehension.

Despite these limitations, the Kelvin scale remains a crucial tool in scientific research, particularly in areas involving thermodynamics, materials science, and space exploration.

Ans. The Kelvin scale is closely related to the concept of thermal energy. In thermodynamics, temperature is a measure of the average kinetic energy of the particles within a substance. The Kelvin scale provides an absolute temperature measurement, where zero Kelvin (0 K) corresponds to absolute zero, the theoretical point at which all molecular motion ceases.

As the Kelvin scale is based on the behavior of molecules, it allows for a direct relationship with thermal energy. With an increase in temperature on the Kelvin scale, the kinetic energy of the molecules also increases, indicating a higher level of thermal energy. Conversely, a decrease in temperature corresponds to a decrease in molecular motion and a lower amount of thermal energy.

The Kelvin scale is particularly useful in scientific and engineering applications where precise temperature measurements and calculations involving thermal energy are required. It allows for more accurate comparisons and calculations involving thermal processes and helps in understanding the behavior of substances under varying temperature conditions.