Question

What are the different scales of temperature? What is the relation between them?

Answer 1

• Celsius scale:

1. The ice point (melting point of pure ice) is marked as 0° C (lower point), and the steam point (boiling point of water) is marked as 100° C (higher point).
2. Both are taken at one atmospheric pressure.
3. The interval between these points is divided into 100 equal parts. Each of these parts is called as one-degree Celsius, and it is written as 1° C.

• Fahrenheit scale:

1. The ice point (melting point of pure ice) is marked as 32° F and steam point (boiling point of water) is marked as 212° F.
2. The interval between these two reference points is divided into 180 equal parts. Each part is called a degree Fahrenheit and is written as 1° F.

• Kelvin scale:

1. The temperature scale that has its zero at - 273.15° C and temperature intervals are the same as that on the Celsius scale is called as Kelvin scale or absolute scale.
2. The absolute temperature, T and Celsius temperature, T_C are related as, T = T_C + 273.15 eg.: when T_C = 27° C,
   T = 27 + 273.15 K = 300.15 K

• Relation between different scales of temperature:

`("T"_"F" - 32)/180 = ("T"_"C" - 0)/100 = ("T"_"K" - 273.15)/100`

where, T_F = temperature in fahrenheit scale,

T_C = temperature in celsius scale,

T_K = temperature in kelvin scale.