The measurement involves exposing the catalyst to a gas (usually nitrogen) at liquid nitrogen temperature. The amount of gas adsorbed at different relative pressures is measured, and the BET plot is generated by plotting \( \frac{1}{v\left(\frac{P_0}{P} - 1\right)} \) against \( \frac{P}{P_0} \). The slope and intercept of the linear portion of the plot are used to calculate \( v_m \) and \( C \), from which the surface area is determined.
