The correct representation for Charles' law is
Charles' law is stated as follows:
"The volume of a given mass of gas at constant pressure is directly proportional to its temperature on the Kelvin Scale."
Let V1 be the volume of a certain mass of a gas at temperature T1 and pressure, p. If the temperature is changed to T2, while keeping the pressure constant, its volume changes to V2 .
As V α T or VT=constant.
Hence, the relationship among the four variables V1 , T1 ,V2 , and T2 is as follows:
V1T1=V2T2 (Pressure and mass constant)