Question

The upper fixed point of Kelvin scale is

• A. $373K$
• B. $273K$
• C. $100K$
• D. $212K$

Answer 1

The correct option is A

$373K$

Step 1: Understanding Kelvin

1. Thermometer measures temperature in celsius
2. The upper fixed point on a thermometer is the highest measurable temperature on that thermometer.
3. In a thermometer highest measurable temperature is ${100}^{o}C$.
4. In the Kelvin scale, the temperature is expressed in Kelvin. In the SI system, Kelvin is the unit of temperature.

Step 2: Calculation:

The temperature in Degree Celsius can be converted to the Kelvin scale as below:

The formula for converting temperature from Degree Celsius scale to Kelvin is

$$\begin{gathered} K=C+273 \\ ={100}^{o}C+273 \\ K=373K \end{gathered}$$

Where $K=Kelvin,C=celsius$

Hence, the correct option is Option A. $373K$