Step 1: Understanding the Concept
For a photon, \(E=\dfrac{hc}{\lambda_{p}}\). For an electron, \(E=\dfrac{p^{2}}{2m}\).
Step 2: Wavelengths
\(\lambda_{p}=\dfrac{hc}{E}\) and \(\lambda_{e}=\dfrac{h}{\sqrt{2mE}}\).
Step 3: Ratio
\(\dfrac{\lambda_{p}}{\lambda_{e}}=\dfrac{hc}{E}\cdot\dfrac{\sqrt{2mE}}{h}=c\sqrt{2m}\,\dfrac{1}{\sqrt{E}}\).
Step 4: Result
So the ratio is proportional to \(\dfrac{1}{\sqrt{E}}\).
Final Answer:
The ratio of photon wavelength to electron wavelength is proportional to \(1/\sqrt{E}\).
\[ \boxed{\text{(D) }\dfrac{1}{\sqrt{\mathrm{E}}}} \]