$\begin{array}{1 1} \text{Since the de- Broglie wave length has a fixed value } \lambda \text{has a physcial significance} \\ \text{Absolute value of energy E of any particle is arbitrary to with in an additive constant. So frequency has no direct physical meaning } \\ \text{Absolute value of energy E of any particle has a direct physical meaning } \\ \text{ All the above } \end{array} $