Concept:
Surface tension is defined as force acting per unit length.
So,
\(\displaystyle \text{Surface tension}=\frac{\text{Force}}{\text{Length}}\)
Step 1: Find the dimensional formula of surface tension.
Force has dimensional formula:
\(\displaystyle [F]=[MLT^{-2}]\)
Length has dimensional formula:
\(\displaystyle [L]\)
Therefore,
\(\displaystyle [\text{Surface tension}]=\frac{[MLT^{-2}]}{[L]}\)
\(\displaystyle =[MT^{-2}]\)
Step 2: Check Energy per Area.
Energy has dimensional formula:
\(\displaystyle [E]=[ML^2T^{-2}]\)
Area has dimensional formula:
\(\displaystyle [A]=[L^2]\)
So,
\(\displaystyle \left[\frac{\text{Energy}}{\text{Area}}\right]=\frac{[ML^2T^{-2}]}{[L^2]}\)
\(\displaystyle =[MT^{-2}]\)
Step 3: Compare both dimensions.
Surface tension:
\(\displaystyle [MT^{-2}]\)
Energy per area:
\(\displaystyle [MT^{-2}]\)
Both are the same.
Step 4: Final conclusion.
Hence, the correct answer is:
\(\displaystyle \boxed{\text{Energy / Area}}\)