Question

In which of the following pairs of temperature scales, the size of a degree is identical?

• A. Mercury scale and ideal gas scale
• B. Celsius scale and mercury scale
• C. Celsius scale and ideal gas scale
• D. Ideal gas scale and absolute scale

Answer 1

Answer: (C), (D)

Celsius scale and ideal gas scale
Ideal gas scale and absolute scale

Celsius scale is developed based on freezing point $\left(0^{o}C\right)$ and boiling point$\left({100}^{o}C\right)$ of water at standard atmosphere. Where the scale is divided by $100$ equal parts between these points
Ideal gas scale is based on ideal gas law.The pressure of an ideal gas varies linearly with temperature if the volume of the gas held constant. By extrapolating $P-T$ graph as $P$ approaches to zero, $T$ is also zero which is called absolute zero of temperature
Absolute scale: It is developed based on fundamental laws of thermodynamics. A Carnot engine has $100\%$ efficiency if we maintain the sink temperature at absolute zero. It is also known as thermodynamic scale of temperature.
Both ideal gas scale and absolute scale equals numerically at every point.
These two are related to Celsius scale by
$T=t_C+273.15$
the size of a degree is identical in the above three scales
option (C) and (D) are correct answer