Which statement about the height of a theoretical plate H is true?

Which statement about the height of a theoretical plate H is true?

• A. H = L/N; lower H indicates better efficiency.
• B. H = N/L; higher H indicates better efficiency.
• C. H is independent of L
• D. H equals tR - tM

Answer: (A)

Height of a theoretical plate, H, is a measure of how much column length is represented by a single theoretical plate. It is defined as H = L/N, where L is the column length and N is the number of theoretical plates. This means that for a fixed column length, increasing the number of plates reduces H, giving sharper peaks and better separation. So, lower H indicates better efficiency. The other statements don’t fit because H is not defined as N/L, it depends on the column length, and it is not a simple time difference like tR − tM. In short, H scales as L divided by N, and smaller H means higher efficiency.

Height of a theoretical plate, H, is a measure of how much column length is represented by a single theoretical plate. It is defined as H = L/N, where L is the column length and N is the number of theoretical plates. This means that for a fixed column length, increasing the number of plates reduces H, giving sharper peaks and better separation. So, lower H indicates better efficiency. The other statements don’t fit because H is not defined as N/L, it depends on the column length, and it is not a simple time difference like tR − tM. In short, H scales as L divided by N, and smaller H means higher efficiency.