$\begin{aligned} & \lambda_{\mathrm{DB}}=\frac{\mathrm{h}}{\mathrm{p}}=\frac{\mathrm{h}}{\sqrt{2 \mathrm{mk}}} \\ & \Rightarrow \lambda_{\mathrm{DB}} \alpha \frac{1}{\sqrt{\mathrm{~m}}} \\ & \Rightarrow \lambda_{\mathrm{a}}<\lambda_{\mathrm{p}}<\lambda_{\mathrm{e}}\end{aligned}$